1^6 On the Hydrometer, 



and that Clarke's is nearly four and a half different from the 

 ftrenglh prefcribed by the ftatute : this is fuppofing the tem- 

 perature to be what fir Charles fays it is confidered by the 

 trade. 



In Ireland the ftandard of proof is ftill more uncertain, no 

 definition of it whatever appearing on the ftatute, but vefting 

 folely on the praftice which prevailed in Enghuid prior to the 

 fld of his prefcnt majefty, viz. mixing water with an equal por- 

 tion of re6tified fpirits of wine, as it is called, no fpccific gra- 

 vity of the fpirit mentioned, and thefpirit, called rectified (pirit 

 of wine, difieriiig materially in point of flrength : neither has 

 the temperature been attended to, the hydrometer there hav- 

 ing no thermometer attached to it: the (landard of proof has 

 coiifequentlv become juft what the maker of the Iridi hy- 

 tlrometer pleafed : the generally received opinion, however, 

 fuppofes it to be nine per cent, over Englifli hydrometer 

 proof. 



Two material imperfc£lions appear in Clarke's hydrometer, 

 exclufive of its complexity ; namely, that neither variations 

 of temperature, iior the gradations of ftrentrths, have been 

 fufficientlv attended to : with refpe6t to the former of thel'e, 

 the fame weather-weight (as it is called by the trade) is ufed, 

 though the temperature ihould vary four or five degrees. 



The inventor, forefeeing that this was liable to weighty 

 objeflions, conceives he has guarded againft it by the direc- 

 tion he gives in a N. B.: but this N. B., fo far from remov- 

 ino; doubts, only fen-es to increafe them ; the words abo7ii 

 and Tiear leaving room for much to be guelTed at, and much 

 more to be apprehended, where the important points it al- 

 ludes to are fo loofely and indiftin&ly defined. 



May I be permitted in this place to explain the confe- 

 quences of this mode of including four or five degrees of tem- 

 perature to be indicated by the lame weight, by liatinga cafe 

 that has frequently occurred? — A merchant in Ireland (hips 

 for London a quantity of fpirit, and previous to its {hip- 

 ment examines the llrength by Clarke's hydrometer: he 

 adjufts the ftrenC'h to be fonit what lefs than xo per cent, 

 (fuppofe 9') over hydrometer proof, the ftrength allowed to 

 be importable without an augmentation duty : this fpirit is 

 per fpecific gravity 910, temperature 55. Suppofe it to be ar- 

 rived in London, but the temperature is then 60 ; notwith- 

 iianding this increafe of temperature (of 5 degrees) the fame 

 weather- weight continues to be ufed in trying the ftrength in 

 Entrland which was applied in Ireland : by this increafe of 

 tenVpcralure, the fpecific gravity being diminifiicd to 907 ihs, 

 when it qomei to be proved in London^ by the fame hydro- 

 meter. 



