variation of the depth of water in a well at detling, maidstone, compared with the rainfall,...

COOKE AND RUSSELL-DEPTH OF WATER IN A WELL 125

V M A T I O N OF THE DEPTH OF WATER IN A WELL AT DETLING, MAIDSTONE, COMPARED WITH THE RAIN- FALL, 1886-1909.

BY RICHARD COOKE, F.R.MetSoc., and SPENCER C. RUSSELL, F. R. Met.Soc.

[Read February 15, 1911.1

THE well of which this paper treats is situate in a yard adjacent to the gardens surrounding “The Croft,” Detling (the residence of Mr. R. Cooke). The weekly plumbings of the water in the well have been taken without any interruption since the year 1885, together with the rainfall for a like period. Detling is situate on the Chalk formation, 359 feet above sea-level, and lies 34 miles north-east of Maidstone, being practically at the foot of the range of the North Downs, which attain a height of 656 feet half a mile north of the well. Half a mile south of the well the Gault crops out, whilst Maidstone is on the Lower Greensand. The mouth of the well is 358 feet above sea-level; and the well was dug, previous to the year 1850, to a depth of 75 feet. During the very dry year 1858 the water supply from the well failed altogether; and in that year it was deepened to its present depth, viz. 118 feet, the whole being in the Chalk formation. Some idea of the thickness of the Chalk in the neighbowhood is to be obtained from particulars of a well at Boxley Grange, about one mile and a half north-west of Detling. This well is 565 feet above sea-level, and the boring showed that the Chalk extended for a total depth of 606 feet, when the Chalk Marl and the Gault were reached. Another well a t Charing, 500 feet above sea-level, arid situate 114 miles south-east of Detling, showed that the Chalk extended for a thickness of 250 feet, when the Gault was reached.l Mr. Clayton Beadle, who originally started the preparation of these records, was unable to complete them, and such data as had been collected were handed over by him.

It was desired to obtain records of the rainfall, not only where the well was situate, but to the northward of it, this being apparently the collecting ground for the water draining to the well. The only places a t which a continuity of the rainfall could be found were Knight’s Place, Rochester, about 9 miles north-west of Detling, and Sharsted Court, Sittingbourne, about 10 miles east of Detling. These places when joined up form a roughly triangular area with Detling a t the apex, the base line from Rochester to Sittingbourne being 18 miles in length. No rainfall record of any duration was to he found due north of the well nor on the high ground of the North Downs. [Mr. Cooke has recently placed rain gauges a t Bredhurst Vicarage, 435 feet up, and at Bicknor Rectory, 550 feet up, which will to some extent supply this want, but as they were only erected in 1908 no use has been made of the records in this paper.]

Memo? of the Geological Sumey of England and Wale4 ‘“l‘he Water Supply of Kent, 1908.

126 COOEE AND BUSSELGDEFTH OF WATER IN A WELL

It is now proposed to briefly set out the data on which the accompanying tables and charts have been founded.

The depth of water in the well is measured every Monday a t 9 a.m., and the record covera a period of 35 years from 1885 to 1909. Only an insignificant quantity of water is ever drawn from the well. The rainfall record at Detling extends Over the same period, and is likewise taken at 9 a.m., the gauge being 350 feet above sea-level Owing to the daily rainfall for the years 1885 and 1886 a t Detling having been lost, although the monthly falls are in existence, the rainfall charted for these years is that at Lower TOY& near Rlaidstone, the monthly falls closely approximating the one with the other.

Knighth Place, Rochester, is 320 feet above sea-level, and is situate on the opposite side of the Medway Estuary to Detling, some 9 miles

ho. I.-Showing the North Domu and the position of the three Wells.

distant in a north-west direction. The daily rainfall here covers the whole period from 1885 to 1909.

Sharsted Court, Sittingbourne, is 287 feet above sea-level, lying about 4 miles to the northward, and below the North Downs, in a parallel line about ten miles east of Detling. The daily rainfall a t Sharsted Court likewise extends for the 25 years.

The rainfall with which the weekly plumbings are compared is that which has fallen at the respective places in the week preceding, includ- ing the measurement on Monday mornings. The 25 years’ average (1885-1909) gives a yield of 25.70 ins. at. Rochester, 25.41 ins. at Sittingbourne, and 27.03 ins. a t Detling, with a mean for the three stations of 26-05 ins.

Dr. Charles P. Hooker in 1903 and 1907 read before the Society two valuable papers on “The lielation of Rainfall to the Depth of Water in a Well at Further Barton, Gloucestershire.”’ This well was sunk in

Qirartcrly Journal of tha Royal Jfdemdqual Society, vol. 29, p. 263, and vol. 33, p. 207.

UOOKE AND RUSSELL-DEPTH OF WATER IN A WELL 127

the Oolite formation, passing into the Fuller’s Earth, and the results obtained by Dr. Hooker showed that it was an extremely sensitive one, with a considerable range in water depth. The well a t Detling partakes of an entirely different character, situate as it is in the Chalk ; sluggishness is its main feature, with a restricted range in water-level, the extreme variation during the period dealt with being 30 ft. 3 ins. Broadly speak- ing, where Dr. Hooker’s well rises or falls in feet, this well rises or falls in inches.

Dealing now with the principal factors influencing the depth of water in the well, these may be grouped under the following heads :-1. The Rainfall; 2. The Season of the Year; 3. Evaporation; 4. Periods of Drought; and 5. The Rise and Fall of the Limit of Saturation. The influences of frost and thaw and that of vegetation are not dealt with, owing to entire absence of any records of the former, and the difficulty of arriving at any satisfactory conclusions relative to the latter.

1. The Rainfall.-The annual rainfall does not appear to bear any close relationship to the depth of water-in the nell. In 1897, the year with the highest average depth of water, via 18 ft. 5 ins., the annual rainfall was nearly 2 inches below the average ; likewise the driest year, 1901, failed to yield the lowest average depth of water. An examination of Fig. 29 and Table 11. shows that the benefit of a wet year gives a maximum yield of water in the next succeeding year. The year 1896 was a wet one, the effect of which was apparent in 1897 ; and again with 1903, which was very wet, the year 1904 obtains a high water-level. Conversely, following a dry year, deficiency of rainfall makes itself felt in a greater or lesser degree in the next succeeding year. The rate and type of fall mainly determine the rise in the water-level, the influence of successive weeks of steady rainfall being clearly visible on the various charts, in contrast with weeks of heavy but intermittent rainfall.

2. The Season of the Year.-The winter rains are of a far more penetrating character than those of any .other season. Falling on ground, as a rule, already moist, and with evaporation at a minimum, this is naturally to be expected.

With spring the effect of evaporation becomes more pronounced, although a certain degree of moisture is still prevalent in the ground. That the spring rains are an important, factor is shown by the year 1898, for on March 21, when the water-level was at the dangerously low reading of 4 ft., a heavy rainfall in the last week of the month checked the fall in level ; and although April was very dry, successive weeks of steady rain in May made their influence felt on the well. Also heavy rains in spring tend to keep the water uniformly high, thus retarding an early fall in level.

Only under exceptional circumstances are the summer rains of a noticeably penetrative character, as in the year 1903. Throughout that extraordinarily met summer the water rose steadily, the usual decline in the early summer months being entirely absent. Following wet summers it is seen that the water-level rises very much earlier in the autumn, and to a much greater extent, there being little or no delay in the penetration of the succeeding autumn rains. The years 1896 and 1909 illustrate this feature very clearly.

As a general rule the autumn rains exercise but little effect upon the

128 COOKE AND RUSSELL-DEPTH OF WATER IN A WELL

well until the month of December ; falling upon a dry surface their early energies are taken up in saturating the soil and subsoil.

3. Evaporation is undoubtedly a very important factor, but it is a di5cult subject to deal with except in very general terms. In this district we have a large expanse of exposed undulating country, with thin herbage on the chalk downs, and areas of woodland, these and other features all exercising an influence on the extent and amount of evaporation.

In the summer months, with ordinary conditions prevailing, evaporation is probably then a t a maximum, but whether balancing or exceeding the rainfall there is little data to show.

In a paper on the “Rise and Fall of Water in Wells in the County of Kent,”l Mr. Bland of Hartlip Place, Sittingbourne, gives a table showing the comparative records of the rainfall and evaporation for the year 1827 a t Hartlip, but there is no information to show how the amount of evaporation was determined.

,1827. Rain. Evaporation. ins. ins. . . . . . . . January la 3

February 1 March 26 April . . . . . . . . 14 May 24 2a June 12 J u l y . . . . . . . . 1

32 August . . . . . . . 5 September 24 14 October 53 14 November 19 9 December 43 2

TOTAL 3oi %

. . . . . . . 2

F . . . . . . .

3 . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . .

. . . . . . .

. . . . . . . - - . . . .

If these figures are accepted, it would appear that for the year 1827 the rainfall was only in excess of the evaporation by about 6 inches.

4. Periods of Drought, in their influence, are mainly dependent on the height of the water in the well at the time the drought occurs, and this is more especially so in summer. Prolonged drought, provided that the water is a t a high level a t the commencement, is not a serious matter, but the situation becomes critical when a drought sets in with only a partially filled well. In the winter months drought is rapidly recovered from, even though the water should be a t a low level. Following a dry autumn in 1899, the well, in the third week of January 1900, contained only 2 ft. 5 ins. of water, thence several weeks of heavy rainfall sent the water up very quickly to 23 ft. 9 ins. Throughout December 1902 the well failed entirely, and in the second week of January 1903 the plumbing gave only 9 inches of water ; thence, notwithstanding almost complete drought in February, the water rose steadily, and heavy rain in the first week of March caused a rapid rise.

6. The Rise and Fall of the Limit of Saturation (Realm of Nature, H. R Mill) or Plane of Saturation or Water Table (Geology of Wuter Sapply, H. B. Woodward).-Dependent upon an excess or deficiency of rainfall we find a rise or fall of the limit of saturation, and also a

Phil. Nag., 1832, N.S. vol. 11, pp. 88-96.


tendency for such limit of saturation to remain permanently at a high level, with only a restricted variation, it may be for a series of years. Evidence of this fact becomes apparent towards the close of the month of June 1891. In that year, in the week ending July 6, a fall in water- level amounting to 2 ft. 10 ins. took place, this fall being apparently in the nature of a settling down of the limit of Saturation. Therice to the close of August 1895 the rise and fall in the water-level never exceeded 2 ft. 6 ins. (1893) being restricted to 1 ft. 3 ins. in 1892, and as low as 6 ins. in 1894. Notwithstanding this permanent level in the limit of saturation, the annual rise to a maximum and fall to a minimum are clearly traceable throughout the years in which it prevailed. The termination of this period was marked by a sudden fall, during the week ending September 2, 1895, of 3 ft. 4 ins., following upon the driest summer of the series. An examination of the rainfall shows that with 1888 a series of wet years set in, which, with the exception of 1893, prevailed up to 1894, a steady accumulation in the underground water supplies thus going on during this period, culminating, in the middle of the summer of 1891, in the aforementioned high limit of saturation.

We find in May 1908 a tendency for this limited variation in water- level to again recur, prevailing up to the beginning of November 1909.

.The explanation here is not so easily arrived at, as the years 1907 and 1908 were extremely dry ones.

Following a series of dry years the limit of saturation may fall below the level of the bottom of the well, but exactly how low it is not possible to arrive at. In May 1902 an examination of the well showed a strong spring, 3 feet above the bottom, which by December of the same year had entirely disappeared, the well being dry.

Table I., and Figs. 2 to 27, show the depth of the water in the well for each week, compared with the previous 7 days’ total rainfall at Rochester, Sittingbourne, and Detling. In the diagrams the black middle line represents the rainfall at Sittingbourne, the shaded line on the left the rainfall a t Rochester, and shaded line on the right the rainfall at Detling. An examination reveals a marked resemblance one year with another, the real divergences being few.

As a general rule, we trace a rise to a maximum in either April or May, 7 having taken place in the former month, and 6 in the latter; but a maximum may occur as early as February or as late as August. The minimum is usually attained during the month of December ; but, with an absence of summer and autumn rains, occasionally the minimum is postponed to January or February of the succeeding year, or even to March. In the very wet year 1903 a minimum took place as early as August, but this is quite exceptional; minima may also occur from September to November. A normal curve shows a steady rise to a maximum in April or May, and this is followed by a very gentle decline to a minimum during December, when an equally gentle rise sets in again. The curve for the first year of the series, 1885, is an illustration of a normal one.

The average curve, Fig. 28, for the 25 years (1885 to 1909) of the weekly depth of the water in the well, together with the weekly rainfall, shows a gentle rise from the middle of January to a maximum of 15 ft. 1 in., prevailing from the middle to the end of April, continuing into the

130 COOKE AND RUSSELL-DEPTH OF WATER IR A WELL

TABLE I . - ~ I N F A L L OF PRECEDING SEVEN DAYS, COMPARED JVITR DEPTH OF WATER IN THE WELL.

- Week ending

- 1885 'an. 5

19 26

:eb. 2

9 16 23

Uar. 2 9 16 23 30

Ip. 6 13 za 27 4

I2

I1 Ia 25

rune I 8

1 5

2s

I!

21 Aug. 2

1;

31 Srpt. ;

2 2

lU1Y

.2c

1c

2A

Id 21 21

Oct. I: 11 2(

Nov. :

I( 2. 3'

i

Dec. I' 2 21

RAINFALL. II Depth

4 11 Jan. 4 4 11 I1 5 I 18 5 4 25 6 z Feh I 7 0 8 8 10 15

13 6 Mar. I I4 9 , 8 1 s 4' '5 16 6 22 16 10 29 16 10 Ap. 5 I7 2 I2 16 10 19 16 6 26 15 11 1 M a y 3

I 1 0 22

I 0

I4 6 31 I3 7 June 7 13 6 14 I3 1 21 13 o 28 12 8 July 5 I2 I I2 1 1 7 19 I I 5 26 I I I Aug. 2 10 9 9 10 3 16 I 0 I 23 9 8 30 9 4 Sept.6

i

20

I1

6 z j 22 15 6 1

RAINFALL. /I ?p Week Watu ending R WelL

-- It. ins. 1887 7 8 Jan. 3 7 11 I 0 8 7 17 13 I 24 rg 10 31 I7 5 Feb. 7 I9 I4 20 I 21 20 3 28 20 1 Mar. 7 19 10 I4 19 3 21 19 o 28 18 4 Ap. 4 I8 0 11 I7 18

25

14 5 30 14 o June 6 I3 7 I 3 I3 I 20 I2 I 1 27 12 4 July 4 I2 0 I1 1 1 10 18

- k p t h

of Yater I Well.

Fro. 3.

FIG. 4. 131

132 COOKE AND BUSSELGDEPTH OF WATEB IN A WELL

middle of May, with a decrease of 1 inch; thence the curve declines smoothly to a first minimum in early November, with an absolute minimum of 9 ft. 8 ins. in the early part of December.

The following is a brief summary of t h e main features of the individual years comprising the series :-

1885.-A year with an average rainfall a t Rochester, slightly above the average at Sittingbourne, and below the average at Detling. The well showed a continuous and steady rise from the first week in January, and attained a maximum of 17 ft. 2 ins. on April 13. Throughout a dry summer there waa a gradual fall to a minimum of 5 ft. 11 ins. in the first week of December, when the autumn rains began to exercise an influence on the well.

1886.-The Rochester rainfall waa slightly below the average, Sittingbourne being more than 4 ins. in excees, and at Detling just above average. Owing to the dryness of the previous December the rise in the water lagged somewhat, but a wet January caused a rapid increase to a maximum of 90 ft. 3 ins. on March 1. February and March were very dry, and both the summer and autumn rains were light. The water-level declined throughout the remainder of the year, a fall of 1 ft. 5 ins. taking place during the week ending October 4, followed by a rise of 5 ins. to October 18, when a decline to the minimum of 5 ft. 3 ins. took place in the last week of December.

1887.-The rainfall at Rochester and Detling was below the average, but Sittingbourne again showed an excess. Very heavy rain (2.91 ins. a t Sitting- bourne) in the last week of 1886 started the water on an upward grade in the opening week. Although January was comparatively dry, and February even more so, the maximum of 18 ft. 6 ina ws9 attained by February 21. Despite a rather dry summer the fall in the water-level was very gradual. There was again, as in the previous year, a fall of 1 ft. 3 i n s during the week ending October 3, a very heavy rainfall during the 6rst week of September apparently failing to reach the well. The minimum, 6 ft. 9 ins, waa on November 28. A very wet November caused the water to rise in the h t week of December.

With this year a series of years of high water-level set in. The water rose very slowly with slight interruptions, the rainfall being light, until the beginning of March, when steady rains caused it to jump up rapidly, attaining a maximum of 22 ft. 4 ina by April 23. A wet summer, and a very wet July, kept the water steady and a t a high level. A dry September and October notwithstanding, the water never fell below 10 ft. 11 ins., which was reached in the first meek of December. A very hemy rainfall during the first week of November was apparently not felt until the second week in December.

1889.-Notwithstanding a dry January the water rose steadily ; rains with droughty periods prevailed during the winter and spring months, and the maximum depth of water, 24 ft. 4 ins., was not attained until the end of May. The water declined very slowly throughout the summer, and a minimum of 12 ft. 6 ins. waa reached in the second week of November. A wet October started the water on an upward grade during November, and at the cloee of the year the plumbing showed a depth of 13 ft. 5 ine.

1890.-Following a dry November and December the winter and spring raine were heavy, but the water only rose slowly. Two dry weeks in April brought the water-level down 9 ins., but steady rains later effected a recovery, and a masimum of 22 ft. 2 ina waa reached by May 19, the water standing a t thia level for a week, when the gradual summer decline set in. Observe how

1888.-Rain in excess of average.

The year closed with a water-level of 12 ft. 8 ins.


very heavy rainfall (4.14 ins. at Detling) during the week ending July 7 only succeeded in checking the fall in level very temporarily. One of the driest autumns of the series followed, but notvbithstanding this the minimum depth did not fall below 10 ft. 11 ins. (December 8), and a heavy rainfall in the closing week of November exercised an influence on the well during the second week of December.

1891.-The previous autumn drought waa followed by an equally droughty winter and spring. The water in the well rose gradually to the middle of March, when a heavy rainfall tamed a sharp rise. The latter part of March and the whole of April were very dry. The maximum depth of water, 20 ft. 7 ins., was reached on April 20. There was a drop in level of 2 ft. 10 ins. during the week June 29 to July 6, heavy rainfall during week ending June 29 failing to reach the welL During the remainder of the year, with summer rainfall up to the average and a very wet autumn, the water remained very steady and at a high level, the variation being between 13 ft. 2 ins. and 12 ft. 6 ins.

1892.-A year of hardly any variation in the water-level, although a very wet one, Rochester 3006 ins., Sittingbourne 33-00 ins., and Detling 2791 ins. The masimum, 14 ft. 7 ins., prevailed from April 18 to May 16, and the minimum, 13 ft. 6 ins., from December 12 to the close of the year, the extreme variation being therefore only 1 ft. 1 in. The summer was wet, and the autumn raina exceptionally heavy, October rainfall being 5.75 ins. a t Rochester, 8.23 ins. a t Sittingbourne, and 6.44 ins. a t Det1ing.z

The rainfall a t Sittingbourne from October 1, 1892, to March 31, 1893, was the heaviest of the whole series of years, being 21-06 ins., with Detling 17-86 ins., and Rochester 1 5 9 3 ins. April and May were exceptionally dry, the summer throughout being droughty. The water attained a maximum of 1 4 ft. 10 ins. by April 24, and a minimum of 1 2 ft. 4 ina from September 11 to 25, thus showing a range of 2 ft. 6 ins. The water fell slightly during June and July, with a sharp fall of 1 ft. 1 in. during the week ending August 7. Despite a wet autumn there was practically no variation in the water-level, this being between 12 ft. 5 ins. and 12 ft. 1 0 ins.

1894.-An even more restricted range in the mater-level prevailed throughout this year, which was a very wet one-32.42 ins. a t Rochester, 32.69 ins. a t Sittingbourne, and 32.63 ins. at Detling. Steady rains prevailed from January to Xarch, the summer being exceptionally wet and the autumn rains heavy. The water rose to a maximum of 1 4 ft. 6 ins. by July 16, remaining at this level for a month, thence .there was a very slight fall of 6 ins. to a minimum of 1 4 ft. 0 ins. lasting from October 22 to Norember 19. At the close of the year the water had risen to 1 4 ft. 3 ins.

1895.-Avery dry year throughout-21*65 ins. a t Detling (the driest of the series), 1 9 9 0 ins. at Sittingbourne, and 2330 i n s a t Rochester. There was great deficiency from January to April, and droughts in May and June. The water remained high and ateady notwithstanding, ranging between 1 4 ft. 3 ins. and 13 ft. 10 ins. Steady raina in July caused a maximum of 1 4 ft. 6 ins. on August 13. August was dry as a whole, and during the week ending September 2 the water-level dropped 3 ft. 4 ins., this being the largest decrease recorded in a single week in any year, with the sole exception of a week in 1906. The water-level varied irregularly to the close of the year ; September was very dry, the autumn rains being up to the average, but failed to exercise any marked influence.

1893.-Another year of extremely limited variation in water-level.

The water reached a minimum of 6 ft. 10 ins. on December 23.

134 COOKE AXD RUSSELL-DEPTH OF WATER IN A WELL

I Depth

Water of 1 in Well. I

TABLE I.-R,%INFdLL OF PRECEDING SEVEX DAYS, COMPARED WITH DEPTH OF WATEB I N TEE W E L L - c O n t i n u c d .

ending Week f I.$ e: ZJ

I- 1 Week

ending

- 1858

Jan. :

I ( 2: Y

Feb. t 1:

zi

(

zc

Jlar. 5 I1 1s 26

Xp. 2

I i 23 3c

.May 7 14

28 June 4

I 8 25

July 2 9

16 23 30

Aug. 6 '3

27 iept. 3

17 24

3ct. I 8

'5

29 vov. 5

C

21

I 1

20

I 0

22

I2

I9 26

Iec. 3

I7 24 31

I 0

-

- 3 'z:

Y

"04" Week Water endint in well.

Depth of

Water ;in WelL

ft. ins. 1889 I I 5 Jan. I I 6 I 12 6 2

:: Feb.' '3 9 I 13 I 1 I 14 o 2 13 g Mar. , 13 8 I I4 0 II 14 7 2

18 3 4

21 I 1. 21 3 2: 22 4 2f 22 3 May t 22 0 1; 21 8 2<

21 4 2; 21 o June ; - 5 It 19 9 1 ; 19 I 24 18 7 July 1 I 8 2 I 17 2 I! 16 6 2; 16 4 2s 16 o Aug. 5 1s 5 17 15 6 ' 5 15 6 zc 15 4 Sept 7 1s 0 9 I4 9 16 14 6 23 14 0 30 13 I I Oct. 7 I3 8 '4 13 o zr 12 10 28 12 2 Nov. 4 I2 0 I 1 [ I 9 18 [ I 2 2s I I o Dec. 2 I0 11 9 11 4 I6 I 1 1 0 23

4 30 12 8

'5 7 4. ,

ft. ins. 13 4 13 10 14 4

15 5 15 g 16 2

17 8 19 o

20 7 20 g 21 o

21 0

20 g 21 I 21 7 21 11 22 4 21 10 21 7 21 3 21 o 20 I I 20 8 20 0 19 6

18 4 17 g 17 7 16 10 16 7 15 I 0 1s 5 14 10 14 5 13 10

13 6 13 3 13 2 12 7 12 6 I2 I1 '3 I 13 4 '3 5 13 5 13 5 13 5

14 11

20 0

21 o

21 0

I9 3

RAINFALL.

---- 18go ins. ins

Jan. 6 '32 .2:

13 Q I .2, 20 -35 -4: 27 '72 .9:

Feb. 3 66 1.01 I 0 .06 *O'

17 .70 .6: 24 .II .It

Mar. 3 '44 -3: I 0 '23 '31 17 -17 '14 24 1.53 1.3C 31 41 -55

Ap. 7 .04 *Oi 14 .28 -17 21 -76 -82 28 1.31 1.91

May 5 -07 '05 I2 1.34 -94 19 -21 -08 26 -16 -19

June 2 ag -01 9 '42 -35

16 6 3 '35 23 -21 '23 30 .78 -29

July 7 2.49 3'33 14 -67 -88 21 '74 a53

Aug. 4 '33 .28 I I '59 1.01 18 .16 .07 25 1.30 1.13

Sept. I 1.01 -82 8 '02 *or

15 . . . . . . 22 -72 '94 29 . I 1 .05

Oct. 6 -01 -02

13 '19 .14 u) -27 -20 27 -48 a53

Nov. 3 .46 -47 10 -67 -54 17 '25 -31 24 '34 -41

Dec. I 1.87 1.89 8 '15 4 4

15 . . . . . . 22 6 1 .43 29 ... '04

28 -06 ...

I1 I I

1 ft. in 13 I( 14 : 14 i '5 1 15 : '5 8 16 5 17 ; 18 E 18 5 '9 1

20 I 20 IC 20 1

19 4

21 3 21 5 21 I 1 22 a 22 2 22 2

21 9 21 I 20 I 20 0

19 5 I9 0 19 0 18 2 18 I 17 2 I7 2 I7 0 16 10 16 2 16 I

15 5 15 3 14 10

14 5 13 I I I3 6 13 I 12 9 12 3

I I 8 I I 6

I2 0

10 I 1 I 1 11 I2 2 12 6

FIQ. 5.

FIQ. 13,

hQ. 7. 135

138 COOKE AND RUSSELL-DEPTEI OF WATER W A WELL

TABLE I.--BAIXFAU OF P R E C E D I ~ SEVEN DAYS COMP.\BED w m DEPTH OF WATER IN THE WELL-codnuuf.

4 pc

ns.

'29 '43 -66 *34 -59 .37 '40

.70 *81

...

.16 -02

"1 ...

.03

.05

.03

t82

5 3

'03 -46 .25 33 .a 52 29 63 17

06 93 35 29 18 ox 59 69 94 14 29 07

4

40 81 01

...

...

...

...

...

43 I 0

I RAINFALL.

Lc 2 E ;j

-- ins. .55 .36

-93 -37 .47 -35 '52

4 5 2.79

... -10 ... ... ... .OI ... ... .. -55

.45

-01 -72 '04 '30

1.50 68 .78 '52 -11

...

...

.02

... -10

'29 '31 -39 .07

1-64 1.08 1.70 a63 'I4 '24 .65

1-58 1-03 .24 *so

1.02 1-13

I-

endmg : week 1 l-

Depth of

Water in Well

-

we endmg

-.

1892 Ian 4

la 25

Feb. I a '5

29 Mar. 7

14

28 4P. 4

I8 25

Hay 2

9 16 23 30

'une 6 '3

27 'UlY 4

I 8 25

tug. I 8 IS

29 jept. 5

'9 26

I 1

22

21

11

2 0

I 1

22

12

Ict. 3 I 0 I7 24 31

{or. 7 14

28 21

'ec 5 I2 19 26 -

RAINFALL. 11 Depth

of Week Water ending in WelL

-)I-- ft. ins. 1893 12 9 Jan. z I2 9 9 12 9 16 12 10 25 '3 0 30 13 o Feb. 6 I2 I1 '3 I2 I 1 20 I 2 I 1 27 13 6 Mar. 6 I4 I 13 14 4 20

I4 4 27 I4 5 4. 3 l4 I 0 14 7 17 14 7 24 14 7 May. I 14 7 8 14 7 15 I4 5 22 I4 5 39 14 5 June 5 I4 I2 I4 19 14 5 26 14 3 July 3 I4 10

14 I 1 4 3

24 14 3 31 14 3 A w . 7 14 I I4 I4 2 21 14 2 28 14 o Sept. 4 14 0 I1 14 2 I8

17

I 4 3 11 25 I4 0 Oct. 2

9 :j 16 13 10 23

rg I 3 10 II Nov. 36 6

RAINFALL Depth

of Water in Well

- ft. ins I3 4 '3 4 '3 5 '3 5 '3 5 '3 9 13 10 13 I 0 13 I 0 14 0 14 4 14 5 14 5 '4 7 '4 7 14 8 14 10 14 8 14 8 14 9 14 9 14 8 14 5 14 0 '3 7 I3 4 '3 5 I 3 5 '3 5 13 5 13 6 12 5 I* 5 12 7 12 6 12 5 I 2 4 1.2 4 12 4 12 5 12 5 IZ 6 12 6 IZ 6 I2 7 12 7

I 2 8 I2 8 I2 8 I 2 8

I 2 10 I2 I 0

-

FIG. 9.

138 COOKE AND R U S S E G D E P T H OF WATER IN A WELL

TABLE I.-RAINFALL or PRZCICDIX~ SW&W DAYS COMPARED WITH DEFTH OF W A ~ B IN TEE WELL--mntinucd.

Depth of

Water in well.

-

we+ h P

- 1% Jan* ~f

I5

B Feb. 5

I2 19 26

Mar. 5

I9 26

Apr. 2 9 16 23 30

May 7 I4 2 1 28

b e 4

18 25

J ~ Y 2 9 16 23 30

Aug. 6 I3

27 Sept. 3

22

I2

I1

20

I 0 17 24

Oct. I 8 15

29 Nov. 5

19 26

Dec. 3

I7 24 31

22

I2

I0

- WFk i endlng

2 8 2

RAfNFALL.

do; .5 ,c $2 -- ins. *04 -12 '34 '32 .IS .03

-13 -72 .36

r.30 '54 *25 .12

-04 92

... -20

.II

. . . . . .

. . . . . . 9 7

*35 2.62

r.26

. . . . . .

-11

-21 . . . . . . .72 -24 -26 .@ . I 5 .60 -48 -89 1-97

2.68 '32 .83 2-76 .72 1.07 -52 -51

1.63 .98 .37 -58

.22

... ...

11 1 RAINFALL.

ti 2 8

ins. a 0 7

-07 .28 *34 '24 a 0 8

-2s -23 -91 '42 1.07 .54 *33 .23

a3 .16

-02

.Is

-21

.49 2.38

1.16 '41 .81 -16 1-89 2.25 .I8 4 1

-31 1.85 2-15

'43 2.1s -26 -7s 1-65 .81 -9 .% .51 -0:

1.4; -9t

-11

.oo

.2:

.sz

ft.ins. 14 3 14 3 14 3 14 4 I4 4 14 4 I4 4 14 3 14 3 I4 3 14 3 I4 3 14 4 14- 4 14 4 14 5 I4 5 14 5 I4 5 14 5 I4 S 14 '4

14 4 13 10 13 10 13 8 13 6 13 6 I3 6 I4 0 14 1 14 6 I4 4 1 1 o 9 10 9 6 9 7 9 4 g 7 9 8 E 8 o

14 4

7 9 7 o 7 2 7 2 7 0 7 o 6 10 7 o

1896 ins. Jan. 6 a6

13 20 .21 27 .2a

Feb. 3 '23 10 -11 17 *03 24 *33

Mar. z .26 9 1.11 16 -46 23 1.29 30 -46

Apr. 6 -32 I3 -17 20 . I I 27 9 3

May 4 a 0 8 I1 .., 18 ... 25 -36

June I ... 15 2-22 22 9 3 29 .85

July 6 -45 13 .,. 20 -37 27 *35

A u ~ . 3 -99 I 0 .66 17 .07 24 -76 31 -24

Sep. 7 1.33 I4 295

28 1.73 Oct. 5 .36

12 1.03 19 1-26 26 -93

NOV. 2 -56 9 -71 16 -62 23 -04 30 -01

Dec. 7 1.1: 14 a 8 1

28 '44

8 . 8 ~

21 .38

21 -IC

II I

Depth of

Water n WelL

- It. ins. 6 4 6 0 6 7 6 5 6 7 6 5 7 4 7 5 7 5 7 5 7 6 7 6 7 4 8 2 8 9 9 1

; g 9 8 9 8 9 7 9 6 9 9 9 7 9 4 9 0 8 10 8 6 8 2 8 1 7 10 7 7 7 4 7 1 6 8 6 5 6 4 6 2 6 2 6 2 7 0 8 2 8 10

10 9

16 6 18 4 I9 3 19 10 19 6 I9 9

I2 I 0

21 I 0

-

140 COOKE AND BUSSELL-DEPTH OF WATER IN A WELL

1896.--8 dry winter and spring was followed by a very wet summer and autunm. The water remained at a low level until the firat week in October, a maximum of 9 ft. 9 inn being attained by June 8, and a minimum of 6 ft. 2 in& from September 21 to October 6. an extraordinary rise in the well, the water-level attaining to 21 ft. 10 ina in the last week From October 26 to December 7 the water rose 11 ft. The last two weeks in November, being very dry, reduced the water-level a few inches, but steady rains in December soon caased a recovery to 21 f t 10 i n ~ in the last W e e E

Light r a b in January kept the water steady and at a high level. A wet February sent the water up 4 f t 3 ina Heavy rains in March further increased the depth of water to a maximum of 28 ft. 0 ins. by April 5. A rather dry summer brought the water-level down steadily, and an ahoa t complete absence of autumn rains further depleted the supply. The extreme dryness in October and November caused a fall of 2 f t 6 ins. between November 29 and December 6 , to a minimum of 6 ft. 3 ins. by December 13.

1898.-The winter 1897-98 (October 1 to March 31) was the driest of the wries of yearn, the rainfall being 9-48 ins. at Detling, 8.53 inr at Sittingbourne, and 7-70 ina at Rochester, and the effecta of thia deficiency, and the drynese of this year, are noticeable by the low water-level which prevailed throughout. The water remained low, varying irregularly until the close of February ; during March the level dropped to 4 f t 0 ins., and at the commencement of April was still at this point. A- heavy rainfall during the 1sat week of March caused the water to rise very alowly ; but a dry April following, the rise lagged. Steady mine in May and the firat week of June exercised an influence on the well, and a maximum of 8 ft. 2 ins. WBB reached by July 25. Thence to the close of the yenr, with slight interruptions, the level again fell away to a minimum of 4 ft. 0 ins. in the third week of December, a deficit in the autumn rains again

1899.-Qnother comparatively dry year, the effect of the winter rains was not noticeable until nearly the middle of February, when a steady riae from 4 ft. 7 ins. set in, the water reaching a height of 11 ft. 1 in. at the close of March. The water fell slowly throughout a rather dry summer, and very heavy rains during the weeka ending October 2 and November 6 failed to check the fall, a minimum of 3 ft. 7 ins. taking place on December 18.

1900.-The effecta of the heavy rains in the previous October and November were apparently checked by the dryness of December, for the well started this year on a falling grade. January wan very wet, and the water commenced to rise in the fourth week. Bn exceptionally wet February followed, coinciding with the greatest increase in the depth of water in the well, the rise from Febrnary 12 to February 26 being no less than 13 ft. 3 ins. Notwithstanding a dry March, an increase in the water-level still continued, the maximum, 22 ft. 9 $., takq place in the last week of March, The stimmer was again dry, and the water fell steadily, the autumn raine being light. The minimum depth of water, 5 f t 0 ina, waa reached near the close of December.

190 1.-This year was the driest of the series at Sittingbourne and Rochester, 17.67 in^ and 1945 ins respectively, with Detling 22-49 ina January and February were very dry, the water h l h g alowly until the middle of March. Two weeka of steady rainfall in March sent the water up quickly. Light rains in April caused a maximum of 12 f t 6 ina at the close of May. The summa waa very dry, and the autumn rains again very light Two weeks of heavy

Thence to the end of the year there

1897.-The year commenced with the high plumbing of 22 ft. 6 ins.

prevaihg.

The maximum amount, 11 ft. 10 ina, occurred by April 17.


rainfall in December failed to exercise any influence, and a minimum of 3 ft. 6 ins. took place dnring the last week of the year.

1902.-Another dry year, 15-84 ins. at Sittingbourne, 20'99 ins. a t Rochester, and 2 2 4 6 iris. a t Detling, the winter rainfall 1901-2 (October 1 to March 31) being 11'18 ins. at Detling, 9.82 ins. at Rochester, and 9'69 ins. at Sittingbourne. The continued deficiency of rainfall is apparent on the level of the water in the well. Up to the middle of August there were only two weeke in which the rainfall exceeded an inch. June 9 and 16-the water changed irregularly with very alight variations to a maximum of 4 f t 2 in. on June 16, thence it declined to 0 ft. 0 in. in the first week of December. Sep- tember, October, and November were all very dry, and steady rains in December failed to exercise any influence.

In the month of May, with the water-level varying between 3 and 4 ft., Mr. Cooke decided to have the well cleaned out, and, if necessary, deepened. Accordingly, about the middle of the month several men were put to work to empty the well. The attempt was a failure ; the men worked continuously with buckets, endeavouring to empty it, but after several h o d work found they could make no impreasion on the amount of water, which remained constant a t about 3 ft. In the first week of December the well actually went dry, and failed during the whole of that month, during which time the opportunity was taken to clean it out.

1903.-Thk was the wettest year of the period, 38.37 ina. a t Detling, 36.53 ina at Rochester, and 35.17 ins. a t Sittingbourne; and the heaviest summer rainfall (April 1 to September 30), 23'05 ina a t Detling, 21.09 inn. a t Rocheater, and 2 0 3 3 ins. at Sittingbourne.

Fed by the rains of the previous December, the first week of the year gave 1 ft. 11 in. of water in the well, the second week there wm a decline to 9 in. after which, with only average rains in January and February, the water rose rapidly.

This year we have the unusual phenomenon of an almost steady and continued rise throughout the summer montha During June and July, very heavy cyclonic raina fell, aa distinguished from raina of a thunder type, and the evidence of thia peraistent rainfall ia marked by the rapid rise in water level from June 1 5 to July 6.

From August 17 to 31 the water remained stationary with 21 ft-, when a decline to 18 ft. in the middle of October took place. Heavy autumn rains falling on the already saturated ground, caused the water to rise to 25 ft. 6 in. by the last week of the year, thia being the highest level a t the close of any year.

1904.-A year with rainfall below the average, but minter 1903-4 very wet, 17-87 ina at Rochester, 17.68 ins. a t Detling, and 17.02 ina a t Sitting- bourne. The effect of a dry January is apparent, the water falling at the opening of the year, and then remaining steady. A wet F e b r u q caused the water to rise rapidly to a maximum of 29 f t 6 in. in the laat week, the greatest depth recorded with the exception of 1910. With a dry summer the usual fall in level takes place, but with the water remaining high, a minimum of 10 ft. occurring in the last week of the year.

1906.-A year with rainfall just below the average, and the winter 1 9 0 4 5 dry. The water remained at a comparatively low level throughout the year. Raine in January and February were very light, during which the water fell steadily, thence it rose and fell irregularly, more or Ieaa closely following the rainfall. The Bummer rainfall was slightly in excese of the average. Three weeks steady rain in August and September sufied to

142 COOEE AND RUSSELL--DEPTH OF WATEB IN A WELL

TABLE I.-RAIMALL OF PBBCEDINO S E ~ DAYS, COYPARED WITE D E ~ OF WATEB IN THX WmL--eontinZud.

7 kpth of

Vater Well.

- . ins. 4 6 5 0 4 8 4 6 4 5 4 6 4 7 5 3

9 10 0 9

:I 6 : I g

t f 9 [I 6 [ I 6 [ I 7 [ I 8 [ I 3

[O 9

[O 3

9 7 9 3

z I 1

i1 I 0

[ I 0

2

i ;

;;

2 :

; i

LO 0

8 5 8 2 7 10 7 6 7 4

6 3 6 0 6 2 6 6

6 0 5 2 4 6 4 3 3 9

-

-

WFk endmg

1897. an. 4

11 I8 25

?eb. I 8 IS 22

VIU. I 8

' 5

29 4Pr- 5

22

I2 I9 26

la 17 24 31

rune 7 I4

28

May 3

21

rulY 5 I 2 19 26

Aug. 9

S 16

2: 3c

Sept. t 13

27

I f 2:

Nor. 1 E

15

2s Dec. C

13

27

ZC

Oct. 4 I1

21

2c

-

RAINFALL

f ja Fi

tins. 189%. 2 2 6 Jan. 3 2 2 g 10 2 2 10 17 2 2 I 0 24 23 2 3' 25 O~ Feb. 7 27 5 14 27 4 21 26 7 28 27 o Mar. 7 26 10 14 26 7 21 27 4 2.8 28 o Apr. 4 27 10 11 27 0 re 26 4 25 26 9 May 2 26 7 S 25 4 16 24 0 23

16 o 2: 15 4 Aug. I ' 5 2 $ 14 6 I! 13 9 2:

I ? 0

I 2 2 2t

I1 g I< I 1 2 1;

I2 0 Oct. :

I 0 I 1 2r

I 0 2 I 0 0 21 g 6 2l 7 o Dec.! 6 3 I: 7 6 I! 7 4 2t

R A I N F A L L

-ll-1-1- :.ins. 1899. ins. ins. 7 3 J ~ I L 2 1.07 1 . 0 1

6 2 16 1.77 1-41 6 o 23 -49 -89 6 I 30 '23 -27 6 7 Feb. 6 .34 a26 6 4 13 1.25 1-30 6 8 20 .6o -62 7 2 27 6 7 Mar. 6 - 1 1 ... 5 3 13 -36 -29 4 0 20 .02 ... 4 2 27 a37 9 7 4 o Apr. 3 -13 a03 4 6 10 6 5 -73

4 7 24 4 -39 4 I I May I -66 .49

8 . . . . . . 4 9 4 8 1 5 a 4 9 -80

6 6 9 -16 -14

. . . . . .

4 4 17 1-33 1.16

6 o June 5 . . . . . . 6 2 12 . . . . . . 6 4 19 .IZ .IO 6 10 26 -49 -53 7 4 July 3 -93 a83 7 8 I 0 .02 .OS 7 I 0 I7 -04 9 2 8 2 24 .85 -43 8 2 31 .% ... 8 o Aug. 7 .12 -26 8 1 14 .03 ... 7 xo 21 -24 4 7 6 28 98 ... 7 9 Sept.4 1-37 -56 7 7 11 -14 ... 7 4 18 -25 -22 7 0 25 '31 -53 7 I Oct. 2 1-85 319

g -81 1-10 6 2 16 '07 ... 6 7

6 6 23 .o8 ... 6 3 30 *85 *@

5 2 13 1.38 1.08 4 g 20 -04 ... 4 6 27 q ... 4 3 Dec. 4 -22 -17 4 2 I I -42 -46 4 o 18 -11 -24 4 I , 25 .20 .IO

5 11 NOV. 6 3.48 1-49

FIQ. 15.

6z L E

8 of ;: : E

DI 6 S & "LON 0 9 It s 9 DZ 0 4 EI 9 L 9 '230 0 8 6z P 8 ZZ '58 SI 6 8 8 01 8 I *idas o 6

-

Pg: z1. EC.! 81. fo If.

95 SI. PI. E6. EO 98

8L.

€0.: H. 52- PI.

95.1

9p.

EX. 6E- LI.

Eo.

...

...

21. OZ.

...

... 11.

... zz. ...

68. zo. 10. fz. E6. 6L* PL. ZS. LI. 26. 28.

LI. 9z.

fI.

IZ.

20.

I z. 11. 80. *sn! - z t P H -

PS of 0 s Ez 2 s 91 9 s 6 9s

8Z 0 8 It E 8 PI L 8 L 'PO o 6 oE S 6 €2 8 6 91 o 01 6 s 01 z-~das 6 01 92 z I1 61 6 II ZI I ZI S *8ng 9 ZI 62 o .€I zz 9 €1 SI 0 PI 8 0 s1 I Lpl 0 SI +z 9 SI 41 E 91 01 0 LI f aunl 6 LI Lz z 81

€I f 61 9 LEJ~ 6 61 62 9 oz

SI 9 IZ

xdy 6 zz sz 9 zz 81 t zz

P*nqq c 81 sz 0 ZI 81 0 s I1 f t t 'qaJ 01 c 8' z E IZ s z PI 1 z L .ae[ 0 f

OZ 01 81

ZZ 0 It

0 ZZ

I1 0 IZ

I061 'SU! -11

FIQ. 17.

FIG. 18.

FIQ. 19. 145

146 COOKE ABD B U S S E W D E P T H OF WATER IN A WELL

TABLE I.-RAINFALL OF PBECEDING SEVEN DAYS, COMPARED WITH DEFTE OF WATER IX TEE WE~L--continuccl.

Week endig.

- I903

Jan. 5 I2 14 26

Feb. 2

9 16 23

Mar. 2

9 16 23 3c

Apr. 6 I3

.27 4

I8 25

'5

29 July 6

13

27

17 24 31

Sept. 7 I4

28

2C

I 1

June : 22

20

Aug. 3 10

21

Oct. 5 I2 19 26

Nov. 2

9 16 23 30

Dec. 7 14

,21 28

*35 11 3 23

FIQ. 22. 147

148 COOKE AND RUSSELL-DEPTH OF WATEB IN A WELL

TABLE I.-BAINFALL OF PEECEDIXQ S ~ v m DAYS COMPARED WITH DEPTH OF WATER I N THE WELL--cmrtinucd.

"%& Water D Well.

RAINFALL.

WFk eodmg.

-1-1- R. ins. 510 6 6 6 z 6 9 8 o g 6 10 6 I1 3 1 1 9

I2 3 13 0 13 6 13 9 '3 6 13 z 13 6 14 o 15 0 14 o I4 6 15 o 13 6 13 0 '3 6 13 a '3 6

12 0

12 I 0 12 6 I Z 6 12 4

g I 0 g o 8 I 0 8 4 g 0 9 0 g 0 9 0 9 4 9 4 g 10 I1 0 11 0 6 2 6 6 6 8 7 0 7 6 7 6 8 2

I 2 0 I2 0

1go6 ins. ins ran. I '29 -30

8 1.32 1-07 '5 -98 4 2 22 1.64 1.01

1907 la. 7

14 21 2.5

Feb. 4 I I 18 2s

Mar. 4

IE 25

Apr. I 8 IS 22

25 May t

13 2c 27

June 2 IC 11 24

July I . E

1s 2i

z( Aug. :

15 2t

Sept. :

x i 2: 3c

Oct. 5 14

2t Nov. 4

IE

25 Dec. I

c It 2! 3c

I1

I i

C

2'

I 1

29 34 '32 Feb. : 1 :IO 1 -10

I9 1.34 :z I 2 .55

26 .IS .14 Mar. 5 a6 *OZ

12 .40 .34 I9 ,27 -35 26 .59 .61

Apr. 2 .03 '14

16 ... ... 23 '31 -40 30 ..p -38

May 7 QI -29 14 -14 a 2 21 1.17 28 *53 *41

June 4 '31 .68 I1 ... ... 18 -52 -41 25 .45 'I9

July 2 1.60 I * O ~ 9 - -18 ...

16 .17 -64 23 '14 .16

13 .og ... 20 .38 -18 27 .06 -13

Sept. 3 -01 ... 10 .51 -30

g ... ...

30 1.34 1.08 Aug. 6 '14 ...

24 1.12 Oft. 17 I I 9 1 .35 I .37 ...

8 1.06 *8g 15 '72 .IS 22 .40 ,40 29 ,62 -54

12 2.20 1.31 19 1.19 1.38 26 .41 e39

Dec. 3 .II .16 10 .26 .15 17 49 *57 24 -03 ... 31 .81 -58

NOV. 5 2.85 2.55

I WelL

tins. 1go8 8 6 Jan.6 9 0 13 9 4 20 9 8 27 ro o Feb. 3 ro 6 I 0 [I 0 I7 [ I 6 24 12 o Mar. 2 rz 6 9 '3 o 16 [3 9 23 14 6 30 rg 6 Apr. 6 r6 o 13 17 0 20 r7 6 27 r8 o May 4 18 o I1 t7 6 18 17 0 25 r6 3 June I

14 9 15 t4 0 22 13 0 29 t2 3 July 6 I 1 0 '3 to 6 20 10 0 27 9 6 Aug. 3

10 9 I7 [ I 0 24 X I o 31 to g Sept. 7 10 9 I4 to -6 21 to o 28 g 0 Oct. 5 8 6 12 8 6 rg 8 6 26 7 6 Nov. 2 7 0 9 7 o 16 7 0 23 6 6 30 6 6 . Dec. 7 7 0 I4

2 28

15 6 a

to 0 I0

21

RAIN?ALL. 3epth

of Water I Well

- t. ins 7 9 7 9 8 2 8 3 8 4 8 5 8 6 8 9 9 0 9 6

10 6

12 6 12 9 12 9 I3 0

12 7 12 6 12 5 12 5 12 4

I 0 0

I 1 0 I2 0

I 2 10

I2 2 I2 0

11 9 11 7 11 7 11 3

10 7

I 0 10 I 0 I0

I 0 I0 I 0 I0 I 0 I0 I 0 I1 I1 0 I1 2 1 1 6 11 6 11 7 11 9 I1 I0 I1 I 0 I 2 I 12 3 12 4 12 4 12 5 12 5 12 6

Fxo. 24.

Txo. 25. 149

150 COOKE AND RUSSELL-DEPTH OF WATER IN A WELL

TABLE L-RAIS?ALL OF PBECEDIRO SEVEX DAYS COXPABED WITH D e m a OF WATER IN TEE WELL--eonlinucd.

welck ending

1909. Jan. 4

18 11

I Feb. 'I I I s t

IS Mar. I

8 '5 29

April 5

I9 26 3

I7 24 31

June 7 14

28 July 5

22

22

I2

- I 0

21

I2 19 26

Aug. 2 9

16 23 30

Sept. 6 13

27 Oct. 4

18 25

Nov. I 8 15

20

1 1

22

29 1 Dec.

I 20 27

RAINFALL Ik$h wuu in Well.

Week ending

1910. Jan. 3

I 0 17 2i 31

Feb. 7 I4

28 Mar. 7

I4

28

18

21

21

APd 4 11

25 May 2

9 16 23 30

June 6 13

27 M

RAINPALL I Depth

of Water in WelL

-- ft ins. 21 6 2 4 0 25 6 25 9 26 o 26 4 26 10

27 3 27 7 28 o 28 6 29 5 30 0

29 11 29 7 29 3 29 0 28 6 28 o 27 3 26 4

30 3 I

25 14 d


ho. 28.

FIO. 27.

the water up to a maximum of 10 ft 6 h. on September 18, and a minimum of 6 ft. 10 ina took place in the la& week of the year.

A series of heavy r a i n s in January and February asnt the water np steadily, but the maximum waa not attained until May 7, 16 f t , a aimilar reading taking place on May 28. A dry August caused the water to fall quickly, 2 ft. 2 inn, between August 13 and 20. I n November we find a remarkable fall in level, between the 12th and 19th from 11 ft. to 6 ft. 2 ins, no leas than a decreese of 4 ft. 10 ins. the greatest recorded. Looking at the exceptionally heavy rains that fell in the weeks ending November 6 and 12, thin fall w e m very di5cult of explanation. There can be no doubt of the accuracy of the reading, owing to the fact that the observer who took the plumbing on the morning of November 1 9 was 80 surprised at the change in level, that he thought he had made an error, and an

1906.-A wet year, but Bummer dry.

162 COOEE AND BUSSELGDEF'TH OF WATER IN A WELL

independent person waa asked to check the plumbing, which wa8 confirmed. After this remarkable fall which was the minimum reading, the water row gradually, the year cloeing with a depth of 8 ft. 2 ins.

Notwith- atanding very light rains from January to May the water roe, without interruption, to a maximum of 18 ft by May 6. Summer rains were also light, and the water-level declined slowly, with a temporary break in August and September, to a minimum of 6 ft. 6 ina in the first week of December, when steady autumn rains exercised an influence.

1908.-Another dry year, the water rose very slowly during January and February, the mins being light. Steady rains in March and April Bent the water up gradually to a maximum of 13 ft. on Mny 4. There wan a minimum of 10 R 7 inn. on A u p t 17, after which, although there was an absence of autumn rains, the water remained steady and at a high level, 12 ft. 6 ina. during the last week of the year.

1909.-A wet year, 33.13 ins. at Detling, 29.69 ina at Rochester, and 26.68 ins. a t Sittingbourne. The winter was dry, but the summer and autumn very wet. October rainfall amounted to 6.80 ine. a t Detling, 6.23 i n s a t Sittingbourne, and 4.72 ina. Rochester. The water remained steady, and a t a high level, until the close of October, reaching a maximum of 1 3 f t 8 in. which prevailed from March 15 to April 19, thence declining by inchen to a minimum of 12 ft. 1 in. lasting from September 6 to 27. Following the heavy October rains there was a sharp and continued rise to 21 h, 3 ina in the last week of the year.

A remarkable similarity ie apparent between this year and 1896 with reference to the autumn rise in water-level, and the subsequent maximum. In 1896, the water-level, following a wet winter 1895-6, a wet summer 1896, and a very wet winter 1896-7, p o ~ e but from a minimum of 6 It. 2 inn. on October 5 to a maximum of 28 f t 0 ina on April 6, 1897-being an increaw in water- depth of 21 ft. 10 ins. Thin year, with winter 1908-9 very dry, a wet summer 1909, and a very wet winter 1909-10, the rise in waterlevel took place in the same week (October 4) as in 1896, but from a minimum of 12 ft. 1 in., attaining a maximum of 30f t 3 ina by April 4,19 10, the componding week of maximum to that in 1897, the rise in water-level amounting to 18 ft. 2 ina

1910.-The six months of this year are included in order to show the maximum depth of water, 30 ft. 3 ins., that has taken place since the series of plumbinga commenced in 1886. The influence of the very heavy autumn rains of the previous year are apparent at the opening of this year. Jaunary and the fimt two weeke of February were dry, and the riae in the water waa in consequence, checked about the middle of January. Subsequent heavy rains in February and March sent the water up steadily to a maximum in the firet week of April.

Table 11. shows the respective annual rainfalls, with the maximum and minimum well plumbinga, together with the mean annual depth of the water in the well.

1. The height of the spring maximum bears no relation to the subsequent autumn minimum, an explanation having to be sought in the degree of wetneaa or dryneaa, and the type of rainfall prevailing later on in the Seaeon.

2. The maximum and minimum plumbings bear no relationship to the annual rainfall, and little, if any relationship is borne by the annual rainfall to the annual height of the water in the well. An a general rule, the benefit of a heavy annual rainfall accrues to the water-level in the well in the next

1907.-A dry year following the heavy autumn ra ins in 1906.

Thence, with hght rainfall, a steady decline in level is noticed.

From this table it is seen that :-


succeeding.years. Convenely, deficiency in one year is likewise felt by a lowering of the annual water-level in the following year.

3. Commencing with the year 1886, a series of years of high annual water- level aet in, which continued to 1895, being markedly high from 1888 to 1894. A period of low annual water-level prevailed from 1898 to 1902.

TABLE II.-ANNUAL RAINFALL WITK MAXIMUX, MIXIMUX, LYD AXXUAL DEPTH OF WATER IH WELL. -

YEAR.

- L.

Ln &

c 8 !Y

- ins.

25.53 2416 21.83 27.93 26.83 25.81 27.97 30-06 2J.54 32.42 23.30 27.61 23.96 20.03 2568 26-99 1945 20.99 36-53 23.23 2440 2924 2433 ;;:g -

Rainfall.

6 i5

4 ... - - .- n -

ins. 26.41

26.80 2607 2967 26.03 2996 33.00 26.32 32.69 1990 28-87 2399 20-80 22.92 25-17 17.67 1744 35'17 22.76 23.52 24.11 I979 19-80 26-68

2946

-

-

.- 3 - - " a_

- ins. 2 4 9 27.12 24.62 28.27 2984 28.60 27.84 27.91 23.58 32.63 21.65 33.49 24.97 22.89 2401 29.28 22.49 22.46 38.37 24.08 25.33 2994

33-12 :::i: -

e'

; - ins. 25.61 26-91 2442 27.42 28.78 26.81 28.59 30.32 23.8 I

32.58 21.62 2999 2430 21.24 24.20 27-14 1987 20-43 36.69 2335 24.42 27.76 22.90 22.26 2983 -

Depth of Water in the WclL

E ri .- t I I(

2 - It. ins I 7 2 20 3 18 6 22 4 22 4

20 7 14 7

14 6 '4 6 9 9 28 o 8 2

22 9 12 6 4 2

21 0

10 6

22 2

J4 I0

I 1 I 0

29 6

:5 : '3 0 73 8

6

April 13 . . March1 . . February 21 . April23 . . May27 . . May 19 and 26 . April 20 . . Apr. 18 to May I( April 24 . . July 16 to Aug. t August 19. . June 8 . . April 5 . . July 25 and Aug. I April 17 . . March 26 . . May 27 . . June 16 . . August I 7 to 3 I February 29 . September 18 . May 7 and 28 . May 6 and 13 . M a y 4 . . Mar. 15 to Ap. IS

E .- i C

2 - ft. ins 5 I 1 5 3 6 9

IZ 6

1 2 6 '13 6 12 4 I4 0 ' 6 1 0

6 2 6 3 4 0

' 3 7 ' 5 0 ' 3 6

I 0 I 1

I 0 11

0 0 I8 0 'I0 0

5 10 6 2 6 6

10 7 I2 I -

--- ft. ins

December 7 . i 10 7 December 27 . November 28 . December3 . November I I . December 8 . November 30 . Dec. IZ to 26 . Sept. 11 to 25 . Oct. 22 to Nov. I! December 23 . Sept. 21 to Oct. ! December 13 . December 19 . December 18 . December24 . December 23 . Dec. I to 29 . Oct. 12 and 19 . December 26 . Dec. X I to 25 . November 19 . Dec. 2 a n d 9 . August 17 , Sept. 6 to 27 .

I 2 I 12 2

'5 5 17 3 13 0 I4 8 13 10 13 5 13 10

12 3 9 6

7 11 I1 I 1 4 0 2 6

I4 3 '5 0 7 4

I 0 8 X I 8

'3 9

I

11 I

- Absolute Minimum 13 h. 4 ins. . . January a and 9, 1893. ,. 6 o . . m 13 1896.

,, a 5 . . ' 5 1900. 9 , 4 2 . . M a h 18 I ~ I . , I 2 I . . February3 q u a . ,, s 6 . . March 13 IF:.

Table I11 shows the respective winter rainfalls (October 1 to March 31) compared with the subsequent maximum depth of water in the well, and there is clearly some relationship between the two. Proceeding to analyse these results, by dividing them into groups of 5 yean, from the wettest, down to the driest, we find a fairly regular descending sequence is established in the subsequent groups of maxima. Following the 5 wettest winters, and the 5 driest winters, a difference is shown in the subsequent maximum of 13 ft. 8 ins.

The regularity of the winter rainfall in the wettest and driest groups of years, for all three stations, is apparent by the values of the subsequent maxima.

M

154 COOEE AND BUSSELL-DEPTH OF WATER IN A WELL

TABLE III.-Tar WINTER RAPTFALL (OCTOBER 1 To MARCH 31) COMPARED WITB TEE SUBSEQUENT MAXIMUM DEPTH OF WATER IX TEE WELL.

I I Rochester.

ins. 1369 13.35 12.03

962 15.49 15.93 13.21 14.41 15.17 16.19 7.70 1 3 , ~ ~ 17.08

982 11.44 17.87 1 ~ 8 7 13'77 I496 12.96

1 2 i 1 I3 4

12.11

RAINFALL

8ittiagboume

ins. 14.62 16.74 16.96 '355 I 6-26 I 1.23 15.95 21-06 15435 15.41 12.43 1944 '353 12.55 17-29 1053 959 11.31 I792 10.18 11.82 11.73 I 2.67

10.65 1 9.89 16.45 I 1 7 q ?

ROCHSTER- 5 Winters of Highest Rainfall 5 Winters of next Highest Rainfil 5 , I I 1

Winters :/Lowest R a i 6 ~ 1 . SLTTIXGBOURNE-

5 Winters of Highest Rainfall 5 Winters of next Highest Rainfall 5 ,, ,J

Winters di Lowest R a i h l .

.

DETLIX- 5 Winters of Highest Rainfall 5 Winters of next Highest Rainfall 5 11 , I

5 5 Winters d i ~ o w e s t ~air;iall .

.

Detliag.

ins. 12.24 1 4 d 14.84 13.55 15'37 9.96 '429 17.86 I457 14.12 1482 19.12 946 12.97 1685 1394 I 1.18 12.08 17.68 11.0s 13~0 16-44 13.60 11.27 19.71

man.

ins. 13.5 1 1471 14.61 13.20 15.15 1027

3:s 1454 14.64 1414 18.25 8.56 12.91 17.07 11.89 10.20 11.61 17.52 10.71 12.93 1471 13.07 10.40 17.75

ins. 16.70 I477 13.45

9.61 12.21

18.24 15.21 13.92 12-71 '0.59

MBAN OF ROCHESTER, SITTINGBOURNE, DETLIX- 5 Winters ofHighat Rainfall . . . 17.77 5 Winters of next Highest Rainfall . . 14-89 5 8 ,9 . . 14.m 5 . . 12.48 5 Winters :/Lowest ~ a i d h . . . 1003


Table IV shows the respective summer rainfalls (April I to September 30) compared with the subsequent minimum water-level, and

ad

0, r.=l

N

again some relationship is seen between the two. Notwithstanding that the summer rainfall is of a somewhat irregular character, we find for all three stations, taking them as before, in groups of 5 , a regular descending

156 COOKE AND RUSSELL-DEPTH OF WATER I N A WELL

TABLE IV.-TEE S o ~ r m RAINFALL (APRIL I TO SEPTZYBEB 30) COMPARED WITE TEE S n s s i a w ~ ~ MINIXUY DEPTH OF WATER IN TEE WELL.

I

I Rochater. j Sittingbourne I

ins. re99

10. 4 15.47 13.92 14.50 11.87 16.37 7.65

16-79 8.99

14.46 11.53 9 6 3

to91 re95 8.80

11-71 21.09 9.0 I

13.67 9 i 9

1 2 . j j

13.47 15.98

9 5 6

ins. I 1.32 10.64 11.44 11.60 1416 14.46 13.04 1481 8.48

1587 7.19

14.14 1 e r 5 r e 0 3 10.29 8.93 6.7 I 9 4 2

20.33 8.56

13.66 9.03 8.90

'0.59 1 "59

Roc H ESTE R-

5 Summers of Highest Rainfall . 5 Summers of next Highest Rainfall .- 5 5 5 Summers of Lowest Rainfall .

5 Summers of Highest Rainfall . 5 Summers of next H i g h a t Rainfall . 5 ,* 5 8 )

5 Summers of Lowest Rainfall .

5 Summers of Highest Rainfall . . 5 Summers of next Highest Rainfall . 5 ,* 5 ,* 5 Summers of Lowest Rainfall .

. SXI-TINGBOURNE-

. DETLING-

.

Detling. b fun . !

ins.

11.57 I 1.63 I477

16.09 13.27 12.68 7'4 1

17.5' 7.13

I 8.66 1 I . j O 10.48 I 1.70 11.65 9.9'

2s.05 9 3 3

1 4 8 2 1048 12.13 13.13 15.95

11.78

15.48

12.10

ins.

MEAN OF ROCHESTER, SITTINGBOUIINE, DETLXNC- 5 Summers of H i g h a t Rainfall . . . . 5 Summers of next Highest Rainfall . . . . 5 , I , . . . .

. . . . , 5 5 Summen of Lowest Rainfall . . . . .

Subsequent Minimum Height of

Water.

ft. ins. 5 11 5 3 6 9

10 I1 12 6 10 11 12 6 13 4 12 4 14 0 6 0 6 2 6 3 4 0 2 5 4 =

18 o 5 6 5 1 0 6 2 6 6 10 7

2 1 0 0

12 1

Avenge

Subsequen Minima. ft. ins.

or 5

18.25 I Z 3

I208 c 7 14.29 10 6


sequence in the value of the subsequent minimum, until the group of 5 driest summers is reached. The value of t h e subsequent minimum, following the group of 5 driest summers, is to a great extent masked by the exceptionally high minimum that prevailed in 1893. It will be remembered that in this year a period of high limit of saturation had been established for some time, and although the summer of 1893 was the driest but one of the whole series of years, the water-level in the well never fell below 1 2 ft. 4 ins.

ANNUAL RAINFALL

Fro. 29.

Summarising the results we arrive at the following conclusions :- 1. The amount of rain penetrating controls the depth of water in the well. 2. Penetration mainly depends upon the type of rain falling, the season

of the year, and the degree of darupnm or dryness of the soil. 3. Successive weeks of steady rainfall exercise a far greater effect upon

raising the water-level in the well, as compared with weeks of heavy, but intermittent rainfall.

4. The winter rainfall penetrates most readily, evaporation being then at a minimum. Heavy rains in spring tend to keep the water high, thus checking an early fall in level. Only under exceptional circumstances (see 1903) is a d y penetration of the summer rainfall apparent, but wet summers, although not actually causing the water in the well to rise, keep i t up at a higher level, the soil being wet and evaporation lessened in consequence.

5 . As a general rule, the effect of the autumn rains is not felt on the well

158 COOKE AND BUSSELGDEPTH OF WATEB IN A WELL

until the month of December; but following a wet summer, or with a high limit of saturation prevailing, the first steady rains in the autumn exercise an almost immediate effect in raising the water in the well.

6. Following wet winten we find high aubeequent maxima; conversely after dry wintera low subsequent maxima prevail.

7. Following wet summere the succeeding minima are high ; and conversely after dry summers there is a marked lowering of the subsequent minima

8. The effect of heavy rainfall on the amount of water in the well ie, at the best, of only a temporary character. An excessive winter rainfall with a high maximum water-level is no gnarantee against a deficiency of supply later in the season ; the controlling factors occurring after the maximum depth is attained.

9. Following a series of wet years a high limit of saturation is attained; and once this condition is thoroughly established the water remains at an almost constant level throughout the seasom, e x c w or deficiency of rain causing very little effect.

10. With dry years the limit of saturation falls, the water in the well running at a low level. This fall in the limit of saturation may be so grent a3 to pass beyond exercising any influence on the well a t all, the well being dry. The energy of the firat rains, following under this condition of circumstances, is expended upon again raising the level of saturation, and may take an appreciable time, before any benefit accrues to the well.

While we are aware of the shortcomings and deficiencies shown in the foregoing paper, we trust that it may be some little advance towards a further knowledge of the distribution a n d conditions of our underground water supplies. In the Report on t h e “Water Supplies (Protection) Bill,” published in July last, the Committee, throughout their Report, repeatedly emphasise the fact of the regrettable dearth of information regarding geological formations i n connection with underground water supplies, and the absence of trustworthy and indeed often of any information as to the subsoil water supply available in any particular district, and as to the effect of rainfall on the water-levels i n various parts of the country.

DISCUSSION.

hfr. R. COOKE mid that while the paper was i n hand they had found another well on the South Downs, of which the records had been kept from 1836 almost without intermiaaion. In taking the monthly plumbings for the yean 1886-1909 they had found that instead of the maximum being in the months of April and May, it was in February, with January as a good second, and December a little below January. This, he thought, would be an important point to settle all over the country. I t would be of interest to water engineers to diecover whether a well situated in a certain part of the country had its maximum in April and May, while another well in a different part had its maximum in Jauuary and February. I t must be borne in mind, with regard to their paper, that there was undeniably one weak spot, and that waa the absence of any infomation concerning evaporation. They had records of evaporation from the well taken by Mr. Bland, but it was impossible to say how this estimate of evaporation w a arrived at. This wm the only teat of evaporation they had for the locality discnaeed in this paper, and i t was

DISCUSSION-DEPTH OF WATER IN A WELL 159

unsatisfactory. For about six months they had carried on daily plumbing of the well at Detling, and also plumbing of wells on the top, and over the top, of the North Downa They had records from six of these, and had also a Bradford gauge, which waa read monthly at the top of the hill. He hoped theae results might forni a continuation of the work set forth in the paper.

Mr. BALDWIN LATEAX said that they were much indebted to the authors of the paper for the trouble they had taken in recording the fluctuations of the water in the well at Detling. With reference, however, to this particular well he would point out that the fluctuationa showed that i t waa situated in a low position in the watershed in which it waa located, and as a consequence not likely to show any very great fluctuationa with rain ; that he has fonnd in the couree of his long experience in the measurement of wells, that wells located in a similar position to that of Detling receive their water mainly from the higher districts, that passea down through these lower w e b in a wave-like form, and the water begins to rise in the high wells some considerable time before it does in the lower wells; that this waa dne to the fact that the rainfall waa much

-heavier on the tops of the hill4 and a much larger amount of water percolated and the lossen by evaporation were leas in the lower portiom of the diatrict.

Mr. Latham exhibited a diagram showing the water-line in the Detling well compared with four other chalk wella-one at Couldon in Surrey, the Barley well in Hertfordshire, the Chilgrove well in Sussex, and Durman’s well a t Collingbourne Kingeton in Wiltshire. He eaid that it would be noted that there ie a marked similarity between many of the observationa of these wells compared with the Detling well. In the highest w e b in the chalk on the top of the Downs the water-line fluctuates more than 100 feet in the course of the year, and as you descend the valleys till you approach the point at which the spring water ordinarily wcap , the fluctuation is meaenred only by a few inches. Thie, probably, is in a measure due to the fact that the strata are much more open in the lower bede, and the water runs more rapidly away, and the rain, tberefore, does not leave its imprelurion on the well, the w e b being more influenced by the floods which descend from the highest portions of the district paasing through the lower wells at a later period. The year 1898 waa an unusually low water period in the chalk districb, and 80 waa the year 1902, and in some districts, as, for inetance, in the Barley well and in this Detling well, the water was lower than in the year 1898, but in other c89es the water was higher in 1902 than in 1898. He had pointed out the importance of theae well measuremenb aa affecting the conditions of public health, especially in the case of children under 5 years of age. The death-rate seemed to follow in parallel lines with the volume of water in the ground-that is, a low water period produced a high death-rate ; high water, aa a rule, if not following immediately on low water, waa the converse ; therefore if the death-rates were plotted downwards from the top of a diagram and the low waters of the well from the bottom upwards, they would show at once the parallelism between the two lines. With reference to the measurement of w e b , he understood that in this case it was the ‘‘ wet dip ” which is memured. This certainly could never be sufficiently accurate. All well measurements should be made from the ground line to the surface of the water, as wells are liable to change in depth within certain limits ; and, moreover, the use of a cord, which haa to be wetted every time a measurement is taken, alters the length of that cord according to the amount of submersion taking place. To wet a cord means that i t is shortened, and therefore all records of welle should be most carefully memured from a point with a fixed level, to the surface of the water. With reference to the observations of Mr. Bland on well measurements, i t appem that Mr. Bland was one of the pioneere in this question of well measurements. He not only kept a record of the rise and fall in his own well, but he made extensive underground

160 DISCUSSION-DEPTH OF WATER IN A WELL

water surveys of a large part of Kent ; and so important did he consider these observations that he continued them for mme years. With reference to the mode in which evaporation WM meaanred in the year 1827, evaporation WILE measured like all other evaporations in that period, viz., in an open vessel erpoaed to the air, which would give exaggerated results aa to the amount of evaporation for a particular year.

Mr. C. SALTEB suggested that mme of the discrepancies between the curves of rainfall and well depth might conceivably disappear if it were poasible to take account of the rainfall over a somewhat larger It seemed probable that the water level a t Detling wau affected by the rainfall over a large part of the chalk formation, within which one might reasonably expect to find some aort of communication from place to place. Heavy rainfall at a considerable distance from the well would probably take effect later than that in the immediate neighbourhood, and a local drought would be more immediate in ita results than a more remote one ; but the latter could not be ignored RB a factor in producing fluctuations in the water level. He congratulated the authors on the courage with which they had attacked a very di5cul t problem. By so doing they had brought the Society into touch with the work embodied in the recently published Memoirs of the Oeological Survey. The problem of underground water supply stood in need of exhaustive study ; our preciae knowledge of the action of water after it once got into the ground being of a very scanty

Mr. E. GOLD aaid that an examination of the last diagram, which showed the annual variations of the depth of water and of the rainfall, suggested that the connection between the two waa very alight and that other factors than rainfall might have greater inhence on the depth of the water. He therefore suggested to the authors that they should take account not only of rainfall, but also of the motion of the air, the mean temperature, the relative humidity, and the duration of bright sunshine, and find a numerical index of the effect of each of these qnantities-a correlation coe5cient. Statistice for the immediate neighbourhood of the well might not be available, but in the first inatance those for London would aerve.

Mr. W. B. TBIPP Baid he thought the question of eunshine was a most important one, because the variation seemed to follow on the sun in a most remarkable way.

Mr. R INWARDS remarked that no mention had been made of the amount of water drawn off from the w e b in the neighbourhood for drinking and other pnrposea

The PRESIDENT said that he had listened to the paper with very great inter&, and thought the Society waa to be congratnlated on the valuable addition to the mall number of exieting long period recorda He wished to make one suggestion in relation to the attempt to obtain correlation curves with such things aa rainfall, humidity, e k , and that waa that they had a geological problem to deal with, not merely in relation to the permeability of the soil, which would vary considerably, but alw to the position of the well. In the case of an nndergronnd current subject to wavelike variation, they had to deal with the nature of the waves, the extent to which these wavea diminished in amplitude from the upper to the lower level, and also with the rate a t which the actual current movement of water took place. He would suggest that in the absence of opportunities for more elaborate investigation, it might be possible to make use of accurate measurements of temperature. They were accustomed to be content with quite rough measurements, to my or y. They might with advantage follow Dr. Nanaen’s example in work a t sea, which had proved that it waa pomible to take measurements of water temperature to a hundredth of a degree centigrade, or even lesa They generally thought that

M t m

Thin might make mme difference.

DISCUSSION-DEPTH OF WATER IN A WELL 161

the water in a well had a uniform temperature, but it would be worth while trying to see whether there were not differences of a smaller BorL “his might give extremely valuable information about the movement going on in the water underground.

Mr. S. C. RUESELL eaid that with reference to the remarka respecting the temperature of well waters three wells had been plumbed every week at Epaom and the temperature taken. The shallowest of these wells was 57 ft., the next 85 ft., and the deepest 262 ft., and the following results were obtained: the warmest temperature waa in the shallowest well, the coldest in the 262 f t nelL The readings covered a period of about 15 weeks, and were taken to one-tenth of a degree. In the well eituate at “The Durdans,” which is 86 feet deep, experiments are being carried out in order to arrive a t the weekly range of temperature which takea place in the well watera A Sixe’s thermometer ia suspended and set in the well waters, and from a series of three obeervations the following resulta have been obtained : for the week ending January 30 the range between the maximum and minimum was 1’ ; for the week ending February 6, 2O.1 ; and for the week ending February 13, 1O.9; the whole of the readings lying between 60O.3 and 48’2.

Mr. W. H. DINES, in a note to the Secretary, ?&warded the accompanying diagram of the rainfall and depth of water in a well a t Pyrton Hill, Watlington, Oxon, which had-been prepared by hi3 son, Mr. J. S. Dines.

RainfaII and Depth of Water in a WeII at Py-rton HiU.

He eaid that the supply of water for the house ia pumped about every third day, but the pumping does not seem to affect the level, and any way the amount pumped is quite uniform.

Mr. C. BEADLE, in a note to the Secretary, mid : “From the conclusion arrived at a t the end of the paper, it would appear that a closer relationship could be established between the rainfall and the level of the water in the well, if, inatead of actual figures for rainfall, the figurea for the amount of water percolating could be made u ~ e of for purposes of comparison. This I infer from the summary of conclusions Noa 3 and 9. I think it would be generally admitted that any conclusions that could be drawn with regard to them relationshipe, whether it is with the actual rainfall, or the amount of water percolating, can only be considered aa true of the particular well in question, and therefore it would be dangerous to draw general conclusions.

I‘ It aonietimes happens that after a fall of rain the percolation at different depths takes several days to respond to the rainfall ; percolation from a given fall of rain reaching its maximum after sometimes 3 or 4 day4 and taking perhaps a whole week before it ia reduced again to a minimum figure This can be clearly seen on examination of percolation figurea

162 DISCUSSION-DEPTH OF WATER IX A WELL

“Then, again, the ‘rate of response,’ which must vary with each individual we4 is of neceasity a determining factor. It appears probable that the percolation per diem, ad measured by percolation gaugea at a short distance from the aurface, would read differently if meaeured at a greater distance, 90 that these fignrea would tend, aa i t were, to run into one another, tending to obliterate differences in readings of individual days, although perhaps the aggregate amount of water percolating at the different depths might he the m e in the long run. It is poaaible ale0 that in those yeare when a fairly constant level has been maintained, such as in 1893, 1893, 1894, and part of 1895, the percolation baa been fairly uniform throughout this period, and just m5cient in quantity to maintain the well a t a fairly comtant level. I think, therefore, that a very nsefnl ervice might be rendered by comparing theae and other well fluctnatiom with percolation figures, and for such a pnrpoee i t would be advantageous to have daily readings in order to ascertain how far and t o what extent the leveh respond to the percolating water%, and to establish the period of 1 ~ ~ 0 n e e as measured by the time which lapses between the water percolating on the surface and ita effect upon the level of the well.”

Atmospheric Electricity Observations on the I ‘ Belgica ” in 1907. In 1907 the Belqun made a trip into the Kara Sea, and for the first time

atmospheric electricity observations were made in high latitudes on board ship. Lieutenant Rachlew undertook and made observations in the dispersion (Zerstreuung) of electric charges in free air, and of the radioactivity of the atmosphere and snow. The Elater and Geitel apparatus waa used, being mounted on a suitable stand amidship, and great care m a taken to eliminate the flapping movements of the electroscope leaves due to the motion of the ship. The insulations were wefully watched, and, despite the humidity of the air, were kept in pod state.

Twenty-six observations were n i d e aa to the dispersion of electric charges of both signs, and the loss per minute tabulated as a percentage of the initial charge. The average results of these percentages for the cruise were as follows : for the positive charge, a +, 0.98 per cent, and for the negative charge, a - , 1-32 per cent. The proportionality, q, of a - to a + was 1.35. Astonishingly large reaulta of q, high as 11, were obtained on several days, and on such days heavy off-shore winds were blowing. I n general i t was shown thnt the loss of electrical chargu was much leas on sea than on land.

The radioactivity of the atmosphere was detected by the method of Elster and Oeitel, in which the active deposit was collected on a suspended copper wire to a high negative potential. Here the Zamboni pile waa useless a.9 the humidity had destroyed ita insulation. However, the difficulty was splendidly overcome by the use of an induction coil and Leyden jar. In general traces of radioactivity were found, but, aa in the caee of the previous obeervations, the radioactivity was much higher on days when there was a heavy land breeze. Finally in an attempt to determine the nature of the deposit, a curve showing the rate of decay of activity of the d e w i t waa d r a m from experimental obaervatione, and by a compnrison with the curre of Curie and Danne, it was found to be due entirely to radium emanation, no trace of thorium being found.

Unfortunately, owing to an accident to the ship, they were forced to return without wintering in Arctic regions, JM had been originally intended. However, the reaulta obtained are of high scientific importance.-H. F. JORNLItON, Teweu- trial blngncth and Almorphrric Elrctn’city. Baltimore, March 1911, p. 54.

variation of the depth of water in a well at detling, maidstone, compared with the rainfall,...

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