Page:Cyclopaedia, Chambers - Volume 2.djvu/1002

 W A

T

( 34-5 )

4i4by 8, you have 45 and 52 exaaiy. Wherefore, inftcad ol the two Numbers 147 and 170, you may take 52 and So, or 39 and 45, or 45 and 52, K?c.

5°, To come to Praclice in calculating a piece of Watch- work, firft pitch on the Train or Beats of the Balance in an Hour ; as whether a fwitt one, of about 20000 Beats, (the ulual Train of a common 30 hour Yocktt-Watch) or a flower of about i4ooo,(theTrain of the new Pendulum Vocket-Watches) or any other Tram -Next refolve on the Number of Turns the Fufy is intended to have, and the Number of Hours the Ptcce is to go : Suppofe, e.g. 12 Turns, and to bo 30 Hours or 192 Hours, (i. e. 8 Days) (So. Proceed now to find the Beats of the Balance or Pendulum in one Turn of the Fury, by the Direction given under the Word Beat — Thus in Numbers ; 12 : iff : : 20000 : 2ffffffff. Wherefore, 14446 are the Beats in one Turn of the Fufy, or great Wheel, and are equal to the Quotients of all the Wheels into the Balance multiplied together. Now this Number is to be broken into a convenient parcel of Quotients ; which is to be done thus : Firft, halve the Number of Beats res -6S66, and you have 13333 5 then pitch on the Number of the Crown-Whcel, fuppofe 17 . Divide 1333; by 17, and you have 784 for the Quotient (or Turns) of the reft of the Wheels and 1 intons ; which being too big for one or two Quotients, may be beft broken into three. Chufe therefore three Numbers, which when multiplied all together conti- nually, will come neareft 7S4 : As fuppofe 10, 9, and 9, mulnplied continually, gives 810, which is fomewhat too much ; therefore try again other Numbers, n, 9, and 8 : thefe drawn one into another continually, produce 792 3 which is as near as can be, and convenient Quotients. Hav- ing thus contrived the Piece from the great Wheel to the Balance ; but the Numbers not falling out

WAT

-... exaftly, as you Numbers already pitch'd on) the Ouotient will firft propofed ■ correct the Work thus: Firft, (by the Direc- be 12 ; which not being too big tot a fine" tion given underthe Word Beats) multiply 792, the Pro- Quotient, needs not be divided info more and

ofth/crel Wneen nI tl P 'p T"' ^ ' 7 ' ^^^ "* wi " lla " d as in A-M.rgin.__L to of the Crown- Wheel) the Product is 13444, which is half the Hour-hand, the great Wheel which per-

the Number of Beats in one Turn of rbp F,,f„. rk«. CKo Ck 1 V> ___,_„„, r^ wu "-" P"

i i urns or tb

Hour : or it may Beats in an Hour. Then find 'what Qu - '

Such is the Calculation of ordinary Watches tb /hew ths Hour of the Day : lu fach as Jhew Minmes and Seconds: tte 'Proccfs is thus.

i°, Having refolved on the Beats in an Hour ; bv divi- ding the designed Train by ffo, find the Beats in a Minute J and accordingly, find proper Numbers for the Crown-Wheel and Quotients, fo as that the Minute-Wheel mall go round once in an Hour, and the Second- Wheel once a Minute.—

Suppofe, e.g. you mould chufe a Pendulum of fix Inches to go eight Days, with iff Turns of the Fufy ; a Pendulum of S Inches vibrates 93S8 in an Hour; and confequently, di- viding it by 6b, gives 154, the Beats in a Minute. Half thefe Sums are 4S84 and 78. Now the firii work is to break this 78 into a good proportion which will fall into one Quotient, and the Crown-Wheel. Let the Crown- Wheel have 15 Notches, then 78 divided by 15, gives 5 ; fo a Crown-Wheel of 15, and a Wheefand 8 ) 40 (5

Pinion, whole Quotient is 5, will go tound in a. ..

Minute to carry a Hand to mew Seconds. — For a 15

Hand to go round in an Hour to /hew Minutes ; becaufe there are ffo Minutes in an Hour, 'tis but S ) 44 (8 breaking ffo into good Quotients, (fuppofe 10 8)00(7.- and 4, or 8 and 7, igc.) and 'tis done. Thus 8)42(5"

4484 is broken, as near as can be, inro proper <. . •

Numbers. But fince it don't fall out exactly in- 15

to the abovemention'd Numbets, you mutt cor- reft, (as before directed) and find the true Number of Beats in an Hour, by multiplying 15 by 5, which makes 75; and 7 5 by 60, makes 4500, which is half the true Train. Then find the Beats in one Turn of the Fufy ; thus, iff : 192 : : 4500 : 54000 ; which laft are half the Beats in one Turn of the Fufy. This 54000 being divided by 4500, (the true

9)108 (12 8 ) 44 ( 8 8 ) 4o ( 7 | 8) 40 ( 5

or the orown-wneel) the ProduS is 13444, which is half the Hour-hand, the great Whs

the Number of Beats in one Turn of the Fufy 3 then, (by forms only one Revolution in 12

a Rule given under the Word Beat) find the true Number Minute- Wheel will (hew the He

t£?T. u.ii?5._ J __:_ :T h _V l6 ■■ », : = n^ ■ I0C J> 8 « be done by the Minute- Wheel.

IS

which is half the

tient is to be laid upon the Pinion of Report, (by the Rule given under that Word.) Thus, i4 : 12 :*: 12 : 9, the Quo- tient of the Pinion of Report.— Having thus found your Quotients, 'tis eaiy to determine what Numbers the Pinions ihall have ; for, chufing what Numbers the Wheels mail have, and multiplying the Pinion by their Quotients, the Produce is the Number for rhe Wheels. Thus, the Number of the Pinion of Report is 4, and its Quotient 9 ; therefore the Number for the Dial- Wheel muft be 4 x 9, or 34 : fo the next linion being 5, its Quotient n, therefore the grear Wheel muft be 5X11 = 55, and fo of rhe reft.

Such is the Method of calculating the Numbers of a i4 hour mtcb.--Wh.kh Watch may be made to go longer, by leffening the Train, and altering the Pinion of Report! Sup- pofe you would conveniently thicken the Train to iffooo ;

,/"„„,« R ' VCn under the Word Beat ' %• As I

"344-4 :: 12 : 20. So that this Watch will

fay, (by the

7. So that

4)

3*

C

9

5)

55

(

11

5)

45

(

9

5)

40

(

8

17

go 20 Hours. Then for the Pinion of Report Rule given under that Word) As 20 : 12 : : 1- 7 is the Quotient of the Pinion of Report. And as to the Numbers, the Opetation is the fame as be- fore ; only the Dial-Wheel is but 28, for its Quotient is alter'd to 7. — If you would give Numbers to a Watch of about 10000 Beats in an Hour, to have 12 Turns of the Fufy, to go 1-70 Hours, and 17 Notches in the Crown- Wheel : The Work is the fame, in a manner, as in the laft Example ; and thus : As

4) s8 C 7

5) 55 (11

5) 45 ( 9 5) 48 ( 8

17

confequently -- J 170 : : IOOOO : I416SS, which fourth Number is the Beats in one Turn of the Fufv

7083- t_t— J:..:j_i

pie ;


 * le

Watch, at Sea, dignifies a meafure or /pace of four Hours ; becaufe half the Ship's Crew watch and do Duty in their turns fo long at a time.

The Ship's Company is divided into two Parts, the Lar- board Watch, and the Starboard Watch— The Matter of the Ship commands the latter, and the chief Mate the former.

Sometimes, when a Ship is in Harbour, they ivatch but a Quarter-watch, as they call it ; that is, but a quarter of the Company watch at a Time.

The Watch-Gtafs being four Hours, is ufed at Sea to ihift or change their Witches.— There are alfo Half-watch Hour- Glaffcs ; Minute and Half-minute Glaffes ; by which lad they count the Knots when they heave the Log, in order to find the Ship's Way. See Loc-Line.

WATER, Aqua, in Phyficks, a fimple, fluid, and li- quid Body ; reputed the third of the four vulgar Elements. See Element.

Sir /. Newton defines Water to be a fluid Salt ; volatile, and void of Tafte: But this Definition Boerbaave fets afide, inafmuch as Water is a Menftruum or Diffolvent of Salts and faline Bodies, which does not agree with the Notion of its being a Salt it felf; inafmuch as, we don't know of any Salt that ditfolves another. See Salt.

Whether Water lie originally fluid ? Tho Water be

defin'd a Fluid, 'tis a Point controverted among Philofophers, whether Fluidity be its Natural State, or the Eftea of Violence : We fometimes find it appear in a fluid, and fometimes in a folid form ; and as the former in our war- mer Climate is the more ufual, we conclude it the proper one, and afcribe the other to the extraneous Action of Cold. ■ — Boerbaavc, however, afferts the contrary, and maintains

i,,if, n o„„ !,-•_,. .r 7; 1 ' ..mi-,, il„ — noenmave, nuwevcr, aliens tne contrary, and maintains

tients And W- r '2-^ l J' ? ITO! '4*7 for the Quo- Water to be of the Cryftalline Kind ; fince, wherever a "^tt^Tttlf^L^l^'^^ - ""M" de S rce of K ,- is wanting ,0 keep it in fufion, it

tients, therefore chufe four, as 10, 8, 8, Si 5 whofe Pio- duft into 17 makes 71808, nearly equal to half the true Beats m one Turn of the Fufy.— Then fay, As 170 : 12 :: 71808 : 5049, which is half the true Train of your Watch. And again, ,70 : 12 : : 12 : ^.i, (or 170) 144, which expref- «tl 1 ™ of Re P ort - antl the Number of the Dial-

}<, l 1 ?"" thefe N"" 1 ''" 5 being too big to be cut in fmall Wheels, they muft be varied by the fourth Rule, above thus ;

0*0 (J°

As Or

4) 4o (10

4) 48 ( 8

5) 40 ( 8

5) 33 (61

17

144: 170 : : 34o :425-

170 : 144 : ; 340 : 305.

Then dividing 340, and either of thefe two fourth Proportionals, (as direcred by the Rule) fuppofe by 15, you'll have 1* or Jj ; then the Numbers of the whole Movement will Hand as in the Margin.

readily grows into a hard Glebe, under the Denomination of Ice. See Ice.

Mr. Boyle is much of the fame Sentiment. — Ice, he ob- ferves, is commonly reputed ro be Water brought into a pre- ternatural State by Cold : But, with regard to the Nature of Things, and fetting afide our arbitrary Ideas, it might as juftly be faid, That Water is Ice, preternaturally thawed by Hear. If it be urg'd that Ice, left to it felf, will, upon the Removal of the freezing Agents, return to Water : It may be anfwer'd, rhar, not to mention the Snow and Ice which lie all Summer long on the Alps and other high Mountains, even in the Torrid Zone, we have been ahur'd, rhat in fome Parts of Siberia, the Surface of the Ground continues more Months of rhe Year frozen by the natural Temperature of the Climate, than thaw'd by the Heat of the Sun ; and a little below the Surface of the Ground, the Water which T 1 1 1 chances