On the Hjdromefer. 1 6l 



tary information as has enabled me, by the addition of four 

 coliunns, to remove all doubts and uncertainties on the fub- 

 je6l, by dcnionltrating, from the fpecific gravity of the fpi- 

 rituous' liquor, what the hydrometer indications fliould be 

 of every gradation of llrength. 



In the^Report, which accompanies thefe tables, fir Charles 

 Blagden makes an oblervation which firll fuggcfted to me the 

 utilitv of thefe additional columns. 



" It may very probably be thought right (fays he), for the 

 future ufe of the revenue, to compute another fet of tables, 

 in which the degrees of heat ftanding at the head of each 

 table, the firft column of it fliall be even numbers of fpecific 

 gravity. This would be proper tor looking out at once the 

 quantities of fpirit and water in a mixture from its heat and 

 fpecific gravity." 



Sir Charles, by this obfervation, alludes not to the means 

 of obtaining the hydrometer indication, but to an opinion he 

 had given in his firll Report, in 1790, that the fimpleft and the 

 molt equitable way of levying the duty on fpirituous liquors 

 would be to confider pure fpirit as the true and only excife- 

 able matter, inftead of the relation to the ftandard of proof, 

 and for calculating which one column of the table is a deci- 

 mal multiplier, to afcertain the proportion of this in any given 

 quantity of a fpirituous liquor; an idea which certainly is in- 

 genious, and, at firft view, appears to have the recommenda- 

 tion of fimplicity : but as every difcrimination of ftrength 

 would require an operation of figures, fraftions would un- 

 avoidably occur, from which, and the delay and danger of 

 errors in thefe o|)erations, this mode, I conceived, had been 

 confidered practically inconvenient, and therefore was not 

 adopted. 



The relation to the ftandard of proof having been long re- 

 cognized bv the difi'erent ftatutes, and in commerce, I thought 

 it probable it would not be laid afide; nor was it, as I con- 

 ceived, necelfary to do fo when a means prefented itfejf of 

 rendering this relation to proof equally correil as that wliich 

 he pointed out : and the new fet of tables, which at firft I 

 apprehended he was about to defcribe as ufeful for the reve- 

 nue, were thofe which would deduce the hyilrometer indica- 

 tion of (Irengih from the fpecific gravity of the fpirit at a 

 given temperature. A table for this purpofc would, I con- 

 ceivc(', be iniporlantiv ufeful on feveral accounts: ift, it 

 \vf uld afford a mode of graduating an hydrometer on a cer- 

 tain princii)le; and, 2dlv, lliat as it furninicd a (iaudard for 

 every gra laiion of ftrength, errors could be difcovered in thofe 

 iiiftruiiients that have been graduated by the ddulive mnde oi 



Vol. XIV. No, 54. L coiuparllon. 



