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Show an? Hi one, and the Mercuryin the other; and on the contrary, either an Increafe of Heat, or Decreafe of Weight of the Atmofphere will make it defcend, TH 2, Since there muft of Neceffity be fome Air left in the void Part of the ‘Tube over the Liquor, that Air, by its Elafticity, will tend downwards, and of confequencewill refift the There being fome Inconveniences atctending the Rife of the Liquor, and be comprefs’d by it as it does rife; its Elafticity therefore is thus | i ——-— te eel —= eae es increas’d. Thermometers juftdefcrib'd ; 3- Since it is found from Experience, thata another has been attempted, lefs Degree of Heat is communicated more that fhould meafure Heat eafily to the Spirit of Wine in the Ball thana and Cold by the Rarefaction greater, the Rarefactions of the Spirit of Wine and Condenfation of Spirits are not proportionable to their producing of Wine, tho’ that be vaft- Caufes; efpecially a greater Degree of Heat ly lefs than that of Air, and finds more Liquor in the Tube thana lefs does, confequently the Alterations to which, notwithftanding, the Heat maybe in the Air likely to be much more eafily communicated thanto that ftaglefs fenfible. nating in the Ball. The Structure of this On thefe Accounts, this laft Thermometer, Thermometer is this: On call’d the Florentine Thermometer, (becaufe fome little Pieces of Turme- contriv’d by the Academifis del Cimento) tho? rick is poured a Quantity of it is that which is in common Ufe, is far from Spirit of Wine, which here- being an accurate Meafure of Heat, &§s, To byreceives ared Tin@ure ; which may be added, what Dr, Halley obferves this being done, the Spirit in the Philofephical Tranfattions, ‘That he has of Wine is filtrated again learn’d from thofe that have kept Spirit of through a brown Paper, Wine long, that it lofes part of its expanfive that the coarfer Particles of Force in Courfe of Time. the Root maybe feparated Various Authors have propos’d various therefrom: With the Spi- Methods for finding a fix’d Point or Degree rit thus tinged and prepar’d, of Heat and Cold, from which to account they fill a Glafs Ball with a for the other Degrees, and adjuft the Scale ; Tube; and that all the Spi- fo that Obfervations made at the fame or rit maynot defcend in Win- different Times, in different Places, may be ter into the Ball, it is con- compar’d together. ie venient to put the Ball into Some note the Place the Liquor is at in a Lump of Snow mix’d Winter, when Water begins to freeze; and with Salt; or if the Inftru- again that in Summer, when Butter plac’d near ment be to be made in Summer into Spring the Ball of the Thermometer melts: The inter Water, impregnated with Salt-peter ; and that the condens’d Spirit may fhew howfar it will retire in the extremeft Cold. Ifit be ftill at too great a Diftance from the Ball, part of it is to be taken out; and that the Tube mayn’t be muchlonger than needs, it is convenient to immerge the Ball, fill’d with its Spirit in boiling Water, and to mark the fartheft Point to which the Spirit then rifes. At this Point the Tube is to be hermetically mediate Space they divide into two equal Parts; the middle Point whereof anfwers in their Graduation to temperate Heat ; and each Moiety they fubdivide into ten Degrees, adding four other equal Degrees on each ofthe two Extreams. ~ But this Method fuppofes the fame Degree of Heat and Cold to anfwer to the freezing of all Water, and the melting of all Butter, as alfo that all Thermometers receive the fame Impreffions from the fame Degree of Heat* fealed by the Flame of a Lamp, and at the all which are contrary to Experience. | Sides is to be added a Scale, as in the former Thermometers. Nowthe Spirit of Wine rarefying and condenfing very confiderably, as the Heat of the ambient Air increafes, the Spirit will dilate, and confequently will afcend in the Tube; and as the Heat decreafes, the Spirit will de{cend, and the Degree or Quantity of Afcent and Defcent will be feen in the Scale. Yet as the Ratio of Yefterday’s Heat to ‘To-day’s is not hereby difcover’d, this InftruMent is not ftri¢tly a Thermometer any more than the former, Hereit isto be obfery’d ; Others advife, That the Ball of the Ther- mometer be putina Quantity of Swow and Salt, and the Point the Liquor is at to be noted ; and that thence the Thermometer be removd into a deep Cave orCellar, whither no external Air reaches, fo that the Liquor receiving the Aétion of the temperate Air, mayfhew the Degree of temperate Heat. Andlaftly, they divide the intermediate Space into fifteen id more equal Parts, which they continue beyon¢ each Extreme: But this Method is liable to tn¢ like Inconvenience with the former. ¢ Dr. Halley affumesthat for a fix'd Degree Heat, where Spirits of Wine begin to Bee 1. That as the natural Gravity of the Li- but there is reafon to fufpectthis too, of being quor makes it tend downwards, fo it refifts its precarious: ‘Tho’ after him, M. 4m Afcent out of the Ball into the Tube, and that the moreas it rifes higher ; for which Reafon it were beft to have the ‘Tube horizontal. 4 tains the Degree of Heat, anfwering t¢ Water, for the graduating his mercurial 4 mometer. But as the different fpecifick Cm TH Toa tics of Water argue a different Maf$ and Tex: Laftly, it fuppofes, that if the Effe@ be ture; ‘tis highly probable, that Heat of all produc’ d in the Thermometer by the Heat of boiling Waters is not the fame ; fo that the Point is yet undetermin’d, THERMOSCOPE; [of Siu, Heat, and onto, Iview.] An Inftrument defign’d to fhew the Changes happening in the Air, with refpect to Hear and Cold, The Name of Zhermofcope is indifferently ufed with that of Thermometer : However, there is fome Difference in the literal Import the ambient Air, which is here produc’d by the hot Water, the Air has the fame Degree of Heat with the Water, But none of thefe Suppofitions are true : For as to the firft ; allowing the Heat of the hot Water equally diftributed through the Cold, one Degree of Heat will be diftributed through eleven Parts, two through ten, three through nine, €c, taking therefore equal Bulks of Water, ex. gr. a twelfth Part of each, the Heat will not be double in the one, triple in ment that fhews or exhibits the Changes of another, 9c, Heat, Gc. to the Eye ; and thelatter, an InThe firft Suppofition is therefore erroneous, ftrument that meafures thofe Changes: On and fo is the fecond ; for neither is the Heat which Foundation the Thermometer thould be of the hot Water equally diffusd through a more accurate Yhermo/cope. the Cold ; nor does the Heat of the hot This Difference the Excellent Wolfins taking Water act uniform ly on the Spirit of Wine, hold of, defcribes all the Thermometers in ule #,e. not with the fame Force all the Time of as Thermofcopes ; fhewing, that none of them its Action. do properly meafure the Changes of Heat, €c. For the third Suppofition : The Heat of and that none of them do more than indicate the ambient Air aéts not only on the Spirit of the fame. Wine on the Ball, but only on that in the Tho’ their different Heights, Yefterday and Tube, and therefor e This as well as That will To-day, thew a Difference of Hear ; yet fince be chang’d. they don’t difcover the Ratio of Yefterday’s Dr. Hook, in order to adjuft the Grada Heat to To-day’s, they are not ftri@ly Ther- of a Thermometer with the greater Accuracy. mometers. hath contriv’d and deferib’d an Infrument The Aéa erud. Lipf. propofes a Method of for that Purpofe, in his Micrographia , graduating the common Thermometers fo, as page 38. that the unequal Divifions thereof fhall corThe Wayof filling Tbermofcopes, or fuch refpond to equal Degrees of Heat ; whereby other fmal! Glafs Tubes with Spirit of Wine the Ratio of ‘To-day’s Heat to Yefterday’s will or Water. be meafur’d, and confequently the Thermo/cope Take the Ball of the Glafs, and then warm improv'd into a Thermometer, it gently between your Hands ; then neal it The Method is thus, very well (tho’ gently) before a goodFire, Take a flender Tube about four Palms long, turning itround, that it may be equally warm; with a Ball faften’d to the fame ; pour into it for without this Cautionth ere will be’ Danger Spirit of Wine, enough juft to fill the Ball, of its breaking : Then applyin g the Ball to when furrounded with Ice, and nota Drop the Flame of a Lamp or Candle, turning it over: In this State feal the Orifice of the about in it, heat it as hot as you can, withTube hermetically, and provide fix Veffels, out melting the Glafs; and then {peedily each capable of containing a Pound of Water, immerfi the open End of the Pipe into ng and fomewhat over ; and into the firft pour the Veffel of that Liquor youintendto fill eleven Ounces of warm Water, into the fe- it withal, the Liquor will rife into it, and fill cond ten Ounces, into the third nine, €3¢. it near full. This done, immerge the Thermometer into ‘The Reafon of which Afcent of the Liquor the firft Veffel, and pour into it one Ounce is, that the Air within the Ball and the Tube of hot Water, obferving how high the Spirit being expell’d in great meafure by the Heat, rifes in the Tube, and noting the Point with orat leaft rarefy’d there to a very great Degree; Unity ; then remove the Thermometer into the the immers’d open End ofthe Tube keeps off fecond Veffel, into which are poured two Ounces the Preffure of the circumambient Atmo{phere of hot Water, and note the Place the Spirit on that Part of the Liquor that the Endof the tifes to with two: By thus proceeding,’till Tube covers: But the Atmofphere preffes on the whole Pound of Water is fpent, the In- all other Parts of the Liquor in the open Vefftrument will be found to be divided into fel, and confequently, there beinz none, or a twelve Parts, denoting fo many Terms or De- very fmall Quantity of Air within the Tube gtees of Heat; fo that at two, the Heat is to hinder it) forces it by its Weight up into double to that of one; at three, triple, ec. the Tube, till it gain an Equilibrium with the But Wolfius fhews, that tho’ this Method is Preffure or Weight of the Air without, Plaufible, yet it is deceitful, and built on falfe If the Tube cannot befill’d full enough by Suppofitions ; for it takes for granted, we have this Method, the reft may be fupply’d by a one Degree of Heat by adding one Ounce of {mall Glafs Funnel, the Shank of which muft hot to eleven of cold Water, two Degrees by be drawn out exceeding flender, andinferted adding two Ounces to ten, &c. It fuppofes, into the Orifice of the Tube ; and then’ by that a fingle Degree of Heat aéts on the Spirit blowing, you mayforce by your Breaththe in the Ball of a fingle Force, a double with a Spirit of Wine into the Tube, fo as tofill it double Force, €e, quite, or to what Degree you of the Words ; the firft fignifying an Inftru- pleafe Dr, Hook, |
