On the Hydrometer. 1^3 



to the relative increafe of overproof, were confidered great 

 improvements ; and though, from the conftrudlion of Clarke's 

 hydrometer, it was evident that the variations occalioned by 

 change of temperature were then fome-iubat known ; yet in 

 Ireland the etfccls of thefc variations were conceived fo im- 

 maierial, and the numerous weights attached to this inftru- 

 ment, the difficulty of underftanding it, the certain delay 

 and probability of miftake, were confidered to be fo objeiSlion- 

 ble, that it was deemed better to life an hydrometer which 

 paid no regard to temperature, than to ufe one liable to fo 

 many other objedions. The variations by the ordinary 

 change of temperature being, however, from one to fifteen 

 fer cent., this defeat in the conftru£lion of the Irifh hydro- 

 meter is fo manifett, that it is prefuraed it would be a wafte 

 of time to attempt any demonftration of its incompetency. 



Although Clarke's hydrometer has not been conftrutfed 

 without a reference to temperature, yet this has been at- 

 tended to only in part ; and the inllrument being olherwife 

 very defective, it will be neceflary to exhibit thtfe defeats, 

 in order that they may be guarded againll in fuch hydrometer 

 as fliall be adopted inftead of it. 



Till Clarke's hydrometer was adopted, which, from the beft 

 information I can obtain, took place about the year 1762, 

 proof Ipirit was made bv mixing equal portions of water and 

 the ftrongeft fpirit which could be procured j but it being 

 fonietimes difficult to oljtain this proof fp.'it for comparifon, 

 fuch a mixture was made by order of ihe honourable board 

 of ex'-ife; and it was found, that when fix gallon? of it were 

 mixed with one gallon of water, a wine gallon of the mixture 

 weighed feven pounds thirteen ounces avoirdupoife: the board 

 therefore declared, that the fpirltuous liquor, of which the 

 gallon wcisihcd feven pounds thirteen ounces, ftiould be 

 reckoned one to fix, or one in feven under proof. 



This definition of proof was adopted in order to accord 

 with a mode of examination which had been lono- in ufe, 

 and fandtioued by the board. 



The hydrometer faid to be invented by Mr. Clarke * was 



at 



z<\m'n an addition of ten gallons of water to reduce it to the ftrcngth nf 

 proof; and it IB laid to bt ten per cent, under proof when one hundred 

 gallons contain ten gallons of water more than proof contains. 



* In 1772 tlic States of J-anguedoc olicred a premium for the beft me- 

 moir on the fuhjcit of a'ctn. lining the llreni;th of brandies. This prc- 

 ir.ium was «djudgcd, by the Royal Society of Krance, to M. Bories, M. D- 

 vhofe invtlligation and experiments on this dsflicult fubjcdV have, I himi- 

 l)iy conceive, been iurpalVcd only by thofc of the Royal Society in this 

 (gantry. S^jcalviu^ of the Viiiiuus methods he liaU tried, he r.iys ; " J'tus 



rccouri 



