348 ~lechctniea, Physlcs~ and Chemistry.

in Professor Dove ' s remarks in regard to Mr. E s p y ' s theory of stm.ms: "and as Espy has done, see an upward current as draught- leader (zugfiihrer) at ~he top of a whirlwind, but a glance m e r d y at the. storm-charts of Redfield aud Reid, is sufficient to show how unnatu- ral the supposition is." Important questions of meteorology depe~]- dan] upon a glatice at a el]art, a~]d American meteorology ~ot e(mti- nentaI. The jourtmis quoted in the course of' the paper, are Captain Party 's at Melville Is~al~d; - At~easters, between Ontario m~d l,;Pie, ~' of five y{.;ars ()bservatio{~s at St. Johus, N{;w[bundland i and o[' 0b- servations at {;ambridge, Massaehus.ms. The sweepir G couelusions from su{:l i{~suflh:hmt {/at{ suit wci[ with {l~e negleet o[' tmmet'ous published regsters of authority, but the extraordinary seleetiou of' localities from width to fl:}rm a judgment , eouht hardi ) be expected from any ()tie claimiHg to be ;t meteorological author i ty .

M. C L~.;;,~: X'P;8 NA{ "rIeA~. [NV~:.XT~O~S.

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~nu~zica/,ed 67 C xPvA~x \V..xs~D~cro~, R. N.

.I)}elbre iwoceedimz to {:i',,c a d<scription of theseinstPuments, atM "* ) . . . . , paa'ticuiarly o[ 111{: SiLhmff?~lc o[' :;1( i s. I~. (}16m !i:lt. of t{oel ct\}rt~some

accouter o[' whic.h :~})i}eared itl the M>,w number o[' the Nautical ),t~g- azhic', it ~m\" b, ~, ;ks w(:lI Io >{ate hricffy whist has beeu dot~e in {briner ~hnes, as |o iim£tiu!4 a >tl)stitule f(w U,c comm(:m log, which it. must be confes,~<,d, is a sultieivl~lly primitive method of fflei.tsklril]~ tile SIlo, OCt of a ship.

1. It is said that as D.u' back as the time of A~gustus, it was pro- l}oscd by Vitruvhts, to pass au a x b , or shaft, through the sh:lc of' a .'drip, havil G a \vl~ecl at each extremity ; from the hmer wheel a stor]e tL.H at each revolutioll, aud the uumbdr of stones determiued the rate o[ the vessel's speed.

£e. ~l'He 3~ar{]Ms i){:: Po'<:t]i, who gained a prize from the Fre~]ct{ Academy :fbr his invc.,~tiot~, about the year 1720, proposed to tow a gtC)e air the cud of' a ]oHg Uu{ b cornice'ted with a [eve] 5 which raised a weight at iis other extremity, aw.l poi~Ued out the speed ol~ a gradu- ated are.

£3. M, Pi{ot proposed a m:~ehine composed of two glass tubes~ {he lower end flmneI s}mped, ',rod bent towards the ship's head, in which tit(; water rose aecordi~g {o the rate of the vessel 's g'oinp.

,l. IN{. Saveriett proposed a gJ{,he about Ibm: filet below the smTaee of' the water fixed at tt{e {.:ml of" a l(mg lever, the upper end to raise weights aeeordiug to the degree of' terns]on, and thus give the rate.

5. Tlte Alaxine S~rp(,dlOr of' I lenry De Saumerez~ of Ouernsey, ori beit~g towed asteru of' a ship, acquired a rotary motion which was communicated lo a machine of clock-work oft board, whence the rate was shown on a d i a h

6. Rnssel 's Perpe~.,a{ LoA~ was a spiral machine tow'ed astern much on the same priuctple as that of D e Saumarez .

M r. Cldmenl's Nautical Inventions. 349

7. Foxon's Log, also perpetual, was very similar. s. The. Navivium, by Joseph Gihnore, was composed o f a w h e e l

and I)irfion fixed to the keel of a ship ; its movement was communi- cated ~o d o c k - w o r k within, by means of a metat rod.

9. (]ot]ieb's Pe,'7)e~'ual Log is au instrument nearly similar, with ~lLe addition of a box to guard the exterior wheel-work . . . .

t0. The Ara~dical ])ro~nomeler, of Bot.jamin Martin, is an instrm me~t of the same kind, ol~l 7 1o be fixed to the sid~:.~ of a ship.

t t. IIopkit~son, o[' }"hiladelphia, proposed a metal lever, with a air- ct:[ar plate at the lower eud, against which tile water acted, and was regulated by a spring, all index showiug the rate of" the ship in degrees on a ~-r:~duated arc.

1.?. ]h)uguer~ the eomj)aniou, of l)", la 6ondamme, in his voyage to Peru~ proposed a giol)e, of (i or 7 inches diameter, to be towed asteru, ti~e olher end of' the towin~ iirle to be c(mueeted with a lever 'wh}.d~ :<hot~[(t raise weights aceordi~tg to tile rate of saili~ag.

iS. The l-t?jdroacope of Cotmt I)~ Vaux, proposed ia 1803, consists of ot~e or more globes of six inches diameter sunk ia the water~ level ,.vidt the keel, passing throl@l a vertical copper pip% as near the con. :r.' ~[ gravity ot 'a ship ~s may be ; lhe ~<{obc is eom~ected by a brass ,.~}miu wilh the e td e f a horizontal lever, the other end of which corn- mm~icatt.~s with a brass slide attached to a spiral spring ; this sprhig is iutemlcd to measure exacdv the %roe of the resistance the globe meets with in passing through the wa tch \vhieh is rendered [lifo knots on a dffd, am[ thtm shows the rate of 'a shii;'s saitmg~ or the rate of 'current wller~ at anchor.

t4. An addition to this instrumer G by the Count De Vaux, was to show the ftmotnlt of distance run, t)y ~ comparison betweer~ two docks, or, as he prefbrr<~d~ a dqps.ydra~ or sa.~,A glass, which ran out once ill 60 miles, when it required robe refilled? this machine would give the wtlote distance run, as wcl[ os the rate of" saiht.~g'.

[Captain Beaufort carried out the fbrmer of' these two plans, we beliere, at~d had it fitted to his })oat, d u r i ~ his wolf known and ad- mirable survey of the coast of Karamania , in 1SI2.]

t5. Massey ' s Palent Log, ou the same principle as ~he Marine Surveyor of' De Saumarez , is too well known to need a deseriptiom and as l~tr as our experience goes, shows the distance run correctly.

16. The lflari.nodometer of" Captain Arthur Bingham, R. N., which. in 1s24~ he fitted to the keel of the Tour[at steamer, was somewhat similar to the 2V(tvivium of Gilmore, as [~tr as we can learn.

17. A plan not unlike that of" M. Pitot, (No. 30 was fitted to the Rhadamanthus steamer, Captain George Evans, R. N., in lS30, we believe, but was not found to answer.

l& Mr. Purcell, of t I amburgh , in 18~tl, proposed a square plate, or ~.,a~% to be fixed under water at the lower el~d of a metal rod, the npper end connected with a spring ; the amom~t of torsion is shown on a dial by an index.

19. Ayre ' s Palenl Log" consists o f ' a smalt pear-shaped bail towed astern at the end of a line, the other is carried over a heavy relier

Yore VI, gin) S ~ t ~ s . No. 5 .~Novs~} 'm, 1843 30

~50 Mechanics, Ph.ysics, and Chemistry.

which it turns according to the arnom~t of tension, ar~ index showiag the resistance it). kt~ots.

Lastly. The 5'il&~&'e of M. Cl&ne,~t, which we now propos(; to describe in detail.

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The ~mm% Sillom~lre, is composed of the two French words Si~tage (headway,) a~d mt~lre (m<~sure,) and mig~iI: be well rendered ia E~> gtish, speed-gauge. This it:strument co~sists of a hollow copper bait, fig. 1, about five irmhes in diameter, s~spended under the ship's bob- tom, nearly amidships, fl'om the middle of a beat lever, A, C, abotit five inches lor~g ; one end of this lever movef~ on a joi[lt~ A, its rut-

M. Cl&nent~s Nautical Iavention& 35 t

crum, attached to the lower end of a metal rod which passes vertically through a copper tube, carried from the deck through the bottom O'f the ship near the keel; at the other end of' the, lever is attached a chain~ C, which leads upwards~ and acts upon a second horizontal

2 lever, t~, F', on deem This seeotld lever corresponding to the lower one~ gives motion, by means of' a spring, to an index, which marks on a diat, the speed of the ship expressed m knots, and tenths of a M~ot,

Such is the whole of the apparatus of" the simple Sil[om,;tre. It wi[I he readily understood, thut, as tim vessel moves through the water. the fluid acts upon the batI, which beitm circular, always presents the same section, and causes it lo move aft, dmrcby depressing the ibre end of the lever, which, by the chain, communicates with the dial ou deck. The so:ale, by which to graduate the knots on the dial, was l'otJ, nd by M. C[(~ment after tltlnlei'otls experiments. This instrument in its simple tbrrn~ shows the speed of the vesset, not the amount of distance rum

The Compound Siliom#:lre consists of the same mechanism, with this addition, that the power which moves the index is applied at the same time to a watch, a~d accelerates its movements in proportion to the intensity of' the moving poweb or as the vessel quickens her speed.

A seeotld watch is placed by the side of the first, in order to show how much the fbrmer gains upon the latter; and knowing that ibr every 6 seconds of gain, the vessel will have made a mile, it is easy to know the distance run.

It is evident that this compound instrument is very superior to the shnple on% but its accuracy depends upon the regular going of two good watches, a result not very easily obtai~ed at sea.

The Sub-Marine Ther'mo,neter is a ver\r delicate instrument com- posed of a ribband tbrmed of two metals of' unequal contraction and' expansion, as platina and silver, and rolled it?. the fbrm of" a helix, A, fig. 8, rewind an axis, t3, wMeh turns as the temperature of the water varies. This motion by a train of wheels and pinions is immediately communicated to two poimers on a graduated dial on deck, and which may be read off easily to hundredths e r a degree.

The whole of this apparatus is enclosed in a metal tube, whiclt passes through the bottom well aft in the run of the ship. The helix, or thermometer, is, thereibre, always at a certain depth in the water, say 10 feet below the surface; and it shows instantly every change in its temperature.

As few observations have been regularly made on the temperature of' the water of tile sea at a certain depth, this machine may lead to some novel results.

The Steam [ndicator points out the temperature and consequent pressure of the steam in the boilers. It is composed of a ribband, or blade, of two sensitive metals of unequal expansion, turned in a spiral form ; one end is fixed to the tube, or pipe, in which it is contained, the other eonneeted with a spindle bearing the pointers which indicate the temperature of the steam on a dial on deck, m degrees and tenths

35~ Mechanics, Physics, and Chemistry.

of a degree. This instrument is connected, by" a small pipe, with the boiler, or steam chest, through which the steam reaches the spiral, which instantly causes any variation in temperature to be shown by the dial ot~ deck : it~ high. pressure engines this may be fbuad useful.

The Derivomeler is an instrument somewhat ou the principle of the Sillomt'tre, and intended to measure the drif't of a ship; this i:~ done by a vane placed oa the keel, connected by a rod with a diat-~ the vane, of course, takes the opposite position to the drig of the ves- sel, which is communicated by the turning of the rod to the pointers on the dial ou deck.

The 1)zlcrnal and .Exlern(d T/~e~,'momeger, as its name indicates, is a highly sensitive thermometer, so placed against the wall of ah observatory, or house, as to show the temperature of' the air within and without. The two pointers, which mark this, are on the i;ace of the same dial.

We believe that Her Majesty has ordered such an b~strument to be placed in ot~e of' the apartments in Buckingham Palace.

We now proee(,,d to the trial of the first named three of" these its-, s*ruments, as fitted on board H. b[. S. Blazer, in ,April last.

l{k~ P O R T ,

M'ond<~, 8rd Aprii, 18<t3. - ] [.M. steam vessel Blazer, havh:~g be<~ fitted with three newly-invented instruments by M. CIGment, of Roche- fort, namely, a ~:;il[om(~tre, to measure the rate of speed,~:~ Steam Thermometer , to indicate the temperature of steam in the boilers,--- and a Sub-Marine Thermometer , to show the temperature of the sea at t0 feet below the snrf~tee, was directed to proceed down the river, on trial, having on board M. ClGment, the }nventor~ ?Cir. Cary, who had constructed the present set of instruments, and Mr. Large, of Woolwieh Dockyard, who had superintended the fitting of them in the vessel.

Betbre starting, made a trial ~mder the superintende~ce of Mr. Lloyd, chief engineer, of Woolwich Dockyard, of the temperature of the steam by the steam thermometer, as compared with the elasticity of the steam, as shown by the steam gauge, at each lb. pressure; making due allowance fbr the height of tlle barorneter, and using the temperature as given in Dalton's experiments, corresponding to the inches of 'mercury in the steam gauge. The results obtained were as follows : -

Steam Ther. CentL Inches.

At 55 !bs. pressure, 1st exp. " 2nd do.

iX~Iqal] ~ Temp. by Dalton's tables,

Differenc%

110.4 Barometer, 2!),85 110.2 f le i ' t o f steam gauge , 10.25

l l 0 . S 108.7 40.10

1.6