DISCUSSION-ANEMOMETER COMPARISONB. 185

this connection he would like to emphasise the remark Mr. Dines had made near the close of paper, RS to the desirability of limiting the sizes and proportions of the Robinson instruments, for at present makers seemed to regard this as a matter of absolutely no importance. Then again, these experiments made it clearer than ever that R honse top is an entirely unsatisfactory place for an anemometer, owing to the eddies and deflections of the wind which are invariably set up by the building ; more attention onght certainly to be paid to the qizestion of exposure, and considerable alterations ought to be made in the conditions under which many anemometers were now kept at work. With regard to the sudden changes of direction, of which Mr. Dines had spoken, it was a fact that in well exposed places these wore far less freqnent than was generally supposed, and he did not anticipate that the helicoid or air meter would experience much loss from this cause, provided they were well exposed in a position free froin artificiaUy-caiised eddies.

THE HURRICANE OVER T H E WEST INDIES, AUGUST

18th-19thj 1891,

BY FRANCIS WATTS.

(Commanicated by the Meteorological Council.)

(Plate VIII.)

[Received January 27th-Read April 2Oth, 1893. ]

ON Angust 18th, 1891, a hnrricnne of great violence swept from the Atlantic into the Caribbeau Sea. The following facts have been collected, and from them the extent and movement of the storm can be ascertained.

Taking the information in order from south to north : From Enrbados it is reported that on the evening of August 18th fie

wind was North-west to West, the barometer falling slightly, and the general aspect of the sky indicative of some atmospheric disturbance.

At St. Lucin (August 16th) a t 4 p.m. the barometer began to fall, and continned falling until 7.30 p.m. when it began to rise again (the extent of fall not ascertsincd). The changes of the wind were as follows:-

3 p.m. NNW force 6 5.30 p.m. WNW clo G 6.30 p m . WNW with very heavy i-ain and some sea

7 p.m. WHW force 4 - 5 from the west.

Mnrtiniqzie.

NEW SERIES.-VOL. XVIII. 0

This Island experienced the fill1 force of the hurricane ; the earliest indications of approaching danger were the whitish haze visible on

186 WATTS-EURRIOANB OVER TEE WEST INDIES, AUUC~UST 1 8 ~ ~ . 1 9 ~ ~ , 1891,

the afternoon of the 17th, and the halo round the moon at night; the following observations from LS Monitaztr d~ Ea Mrwlinipue (Journal Offioiel), of August 25th, very well describe the progress of the storm over Fort de France.

‘I The fall of the barometer began at noon, but it did not vary verymuch from normal rate until 4 p.m. At that time the leaden colour of the sky, the squalls which followed each other with considerable force, the barometer, which had already fallen to 758 mm. (29.M ins.), were all signs which combined to give the dam m d warned seafming people to be on their guwd.

‘ I At 5.30 p.m. the barometer stood at 757 mm. (29.80 ins.), and we perceived that Fort de France lay on the track of the cyclone. From that moment the gusts of wind became more violent, the b‘mometer continued its downward movement and thick rain began to fall. - _ ‘‘ The wind blew from North-east without intermission, proving that we were in the line of the centre.

From 7 to 8.15 p.m. the wind blew a hurricane from the North-east ; then suddenly the wind and rain ceased, the sky cleared, and an inexperienced observer would have believed in this treacherous calm. It was the passing of the centre of the cyclone. The barometer had fallen to 721 mm. (W38 ins.)

*IAt 8.30 p.m. the hurricane recommenced, but from the South-west, now com- ing from a direction directly opposite to that from which it had blown at first ; we passed at that moment into the second half circle of the cyclone, celled by sailors the navigable semicircle.’ At 9.30 the hurricane blew furiously, but the barometer rose and the wind veered to the South-east, showing that the phenomenon was leaving. us. At 10.30 there were still strong gusts from the South-east, but comparatively weak, nnd coming like dying gasps of the devouring monster.”

A self-registering barometer is kept at the Club, the Cercle de St. Pierre, and from the diagram’ (p. 187) the movements of the barometer, and the time at which they occur, can be ascertained with great accuracy. The in- strument failed to mark the paper for about 20 minutes, and this unfor- tunately at the time that the centre of the cyclone was passing, hence the full extent of the fall of the barometer mas not registered. From about 6.15 until ncarly 9 p.m. the barometer inadc a serics of rapid rises and falls through n range of about a quarter of an inch.

Froin Dominica it is reported that the barometer fell about two-tenths ofan inch during the morning of the 18th, nnd that the total fall during the day was only about -26 in. or -30 in. Heavy showers fell during the morning, and in the afkrnoon the wind began to blow in violent gusts from the Esst-north- east, increasing in violence up to midnight, the wind slowly veering to East, East-south-east, and by morning to South-east. Lightning was frequent, but there was no thunder.

From the Report of Captain F. W. Powles, R.M.S. Esk, the force of the wind from 8 p.m. until 1 a.m., during which time the Esk was off the islmd, was 10 to 11 of Beaufort’s scale.

The R.M.R. Esk left St. Pierre, Martinique, at 2.30 p.m., thus escaping the full violence of the hurricane. Captain Powles has communicated the following interesting report (p. 187).

1 We are indebted to Mr. Symons for the loan of this block.-EDrroR.

WATTS-EURRIQANF OVER TEE WEST INRlES, 4UGU$T 18TE-l%'H, 1891. 187

AUOUST I7TH. 5 . 3 0 p.m. Left B:irbados for St. Pierre. Fine, but

hazy ...........................

Barogrnm at Msrtiniqne, August ISth-lgth, 1891.

In. NE to ENE, 3-4 30'17

I Extracts from the Log R.M.8. Esk, August ~ ~ t h - ~ g t h , 1891 . I

Midnight. Fine and clear. A film over sky and halo roiincl moon ....................... I ENE. 7 10'20

AUGUST ISTH. 4 a.m. Squally. Sea modornte ................ 6 .. Fine. Arrived at Castries. St. Lucia .... ENE. 4 10'10

188 WATTS-EURRICINE OVEfc THE WEST INDIEIS, AUCtUST 1 8 T E * 1 9 T H , 1891,

AUGUST 18th. 8 a.m. Rainy; nt 8.30 left St. Lucia. Prolonged

squalls and rain ................... 9 .. Overcast with rain ...................... 0 , I Do. ." ................... 9oon. Fine and cloudy ........................ I p.m. Arrived at St. Pierre, Martinique. Moderate

2 ,, Moderate and cloudy. 2.30 left Martinique 3 ,, Strong squalle and heavy rain. Sea rising

from ENE .......................... 4 .. Heavy rain and high 8ea ................ 5 .. Overcast, with rain at timea. i ............ 6 Very threatening sky, but less wind ; a break

in the sky to the West; observed the sun for a few minntes ................

.30 .. Violent squalls and heavy rain ......... 8 I , Do. do. Left Dominica a n d

steered NW by N 9 ,, Violent gale, with terrific squalls and rain

[O I , Do. do. Lightning to the southward. ...

1 1 I , Do. do. H e a T rain .... Hidnight. More moderate ........................ I a.m. Violent squalls. Lightning, thunder and

I .. Overcast Eky .......................... and cloudy.. ........................

7 .. At Dominica. Heavy rain .............

AUWST 19m.

Extracts from the Log R.M.S. Esk, August 17th-1gth~ 18gr-Continued.

heavy rain ..........................

Wind.

ENE to E, I,C-IX Overcast ; squalls less violent ............

DO. do. ............ Very heavy rain and hard squalls

D.o. do. ............ Violent squalls and heavy rain.. Less rain; sky clearer. Guadeloupe in

sight, SE .......................... Weather clearing to SE. Sea high from

SE to S ............................ Weather clearing up rapidly. A henry

bank of alouds sinking to the WNW

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

. .

NE, 7-8 NE to NNE. 7

E to XSE, 9-10 ESEtoSE,g ESE to SE, g

ESE, 9 9% 9

BE, 9

SE to ESE, g

..

NE to NNR; 6 NE to NNE, 5

ENI, 3

ENE, 6-4 ENE, 4

ENE, 7-10

ENE, 10 ENE, I I

ENE to E, II E, 11

E, 7-8

To Noon.

k 0 - ieter

In. p-1 j 10'20

10.17 10'16 10'13

~ 0 ° C

30'07

$0'03 J0.W

".*9t

'9'96 30'01

'9'95

29.9: 29-97

30.01

30.0: 30.0:

30'0: 30'0: 30.0~ 30'0: 30'0( 3 0 x :

30.11

;o.1

.. -

The hurricane wa,s of small diameter, probably not more thnp. 80 miles, but of great violence, the centre passing eyer Fort de France between 8.15 p.m. and 8.30 p.m. of the 18th August ; the direction of the mind changing from North-east to South-west at that time (Le Propnpteui. , quoting Journal Officiel, August 26). The hurricane was of greatest extent north of the centre, for at St. Lucia, 30 miles south of the centre, the wind did not blow wit11 pea t force. From infomation f obtained from the Harbour Master there, the mind] was at 3 p.m. North-north-west, force 6 ; at 5.30 p.m. West-north-west, force 6 ; at 6.30 West-north-west, with very heevy rain

some sen from the westward; at 7 p.m. the rain ceased and the sea went clown. But at Dominica at 8 p.m. the wind was East-north-east, force 10, nearly 50 miles from the centre. The disturbance dicl not reach very high in the atmosphere. While the hurricane mas approaching occ&onal breaks in tbe sky showed the higher clonds to be nearly motion-

WATTS-HURRICANE OVER ZRE WEST INDIES, AUGUST 18TH-19TH, 1891. 189

August. ----

is.. .. . _ 19 ......

€ess. At G p.m. on the 18th at Dominica the sun was seen for a few minutes, when the tipper clouds were not moving with any rapidity. The air was drier than usual in the aclvancing portion of the storm.

"At Dominica I am told that the wind came from the Southward about 11 pm. , and at 2 a.m. the heaviest sea was experienced.

"At Martinique the fall of the barometer is reported to have been as follows :-

Cumulus was seen travelling slowly from north-east.

A t St. Pierre 1.417 ins. At Fort de France 2.165 ins. At Morue Rouge 3.149 ins.

' I This last is so great that I think it probable the height of the barometer above sea level may not have been allowed for.

'( The earliest signs werc in the sky. The haze seen on the afternoon of the 17th and the halo round the moon were unusnal. The barometer did not give any decided warning on board the Xsk.

" The fall of the barometer at St. Pierre was very rapid while the centre was passing over Fort de France, from G to 8 p.m. it fell 1.101 ins., and rose again in the next two hours to about the same height."

From Montserrnt an interesting series of observations has been forwarded

Time.

10 p m . 2 a.m. 9 ( I

10 , I

10.30 9 ,

12-30 > I

2 p.m. 4 9 ,

by Mr. F. Driver.

ENE NE E

ESE . ESE

E SE ESE SE SE

------ Ins.

6 29'65 7 29.62 8 29'64

29.65 29'70 29.6 j 3

6 29'64 5 29'6; 3 29'65

2

Direction. Force' Wind I Barometer.'

* The barometer is an aneroid, situated 400 feet above sea level ; the readings are uncorrected.

Ant ipa was so far removed from the hurricane track as to experience little more than a moderate gale ; the barometer fell very little, but the rapid motion of the lower clouds, together with the steady veering of the wind, pointed to a cyclonic clistorbance to the southward. At 5.30 p.m. the wind was blowing from North-north-east to North-east, and the lower olouds were moving with some rapidity, while an upper stratum of cirro- cumulus cloud appeared quite motionless ; thus confirming Captain Powles' observation that the " disturbance did not resch very high in the atmos- phere." By about 9.30 the wind was East, force 5 , slowly veering to South- east by morning with force 2 to 3 at 9 a m . on the 19th. The greatest force of the mind during the night of 18th did not exceed 6-7. The

190 WATTS-HURRICANE OVER THE %ST INDIES, AUGUST 18TH-19TH, 1891,

August.

18 ...... ........ xg ...... ........

following were the readings of the baronieter at the Goverument Laboratory (corrected for height above sea level) :-

Time. I Wind. I Force. Barometer. ------------ Ins.

g a.m. ENE 4 30.193

9a.m. SE 2 30.122 3 p.m. SE 2 30'07s

3p.m. NE 4 30'12s

I August. I Time,

I S . . .... 4 pm. ........ 8

19 ...... z a.m. , , a ..... 4 ,, ........ 6 .. ,, ..... ./ 8 ,,

------ ........ Middight

........ 10 ,,

Position.

Auguilla Off St. Martin's ofl Saba

Off Etis'talius

Nevis St. Eitts

Off Nevis

Wind.

NNE NE ENE

E E E E

ESE 5 30.06 j 1 30'06

Weather very haey on evening of 17th and morning of rSth.

The subseqiient course of tho storm is described in the Pitot Ckwt of the North Atlantic for September, 1891, published by the Unitcd States Hydrographic O5ce :-'' The data thus far rcceivecl are too incomplete to allow of plotting the track of' the hurricane with any certainty, dthongh it appears to have moved about North-north-west ovor Smto Domiugo, and thence northward and eastwnrcl." The nccompaugiug chart (Platc VIII.) gives the track as plotted on the Pilot Chart, which traces it LIP to tho 28th in GOOW and 35ON.

The facts here given summarise the whole of thc information received respecting this particular storm,