Acrcouirr w idoki. ' 



t>bfervations thus made, he has added accounts of fome mines 

 in Scotland ; a Tour from Glafgow to Staffa ; the fait mines at 

 Northwich ; the Parys Mine ; Obfervations in Wales, and an 

 Account of Mr. Williams's book, in 2 vols, called the Mi- 

 neral Kingdom. This account feems too concife to be of 

 great utility, and as a critique would have amVered its pur- 

 pofe as well, if a few of the epithets had been more civil. 



63 



An Enquiry into the Caufes of the Errors and Irregularities which Speer on the 

 take place in afcertaining the Strength of Spirituous Liquors, by hydrometer. 



. 'the Hydrometer , with a Demonjl ration of the Praclicability of 

 fimplifying and rendering this Injirument accurate. By Wil- 

 liam Speer, Supcrvifor and Ajjayer of Spirits in the Port of 

 Dublin. Oclavo, 48 Pages. London, 1802. 



On the prefent occalion, when the government of the 

 country appears difpofed to fettle this point of experimental 

 philofophy, upon which refults of confiderable importance to 

 the revenue and to private property depend, but which have 

 certainly been hitherto conducted in a flovenly and inaccurate 

 manner, it muft be very acceptable to all parties to fee the 

 fubject clearly treated in a fmall pamphlet. After a fhort In- 

 troduction, the author gives an account of the origin and rife 

 of the hydrometer, the caufes of its irregularities, the different 

 modes of charging overproof ; the principal defects in Clarke^ 

 hydrometer ; the imperfection of the weights in that inftru- 

 ment; the general principles of floating inftruments; the 

 ftandard of pure fpirit ; Gilpin's tables j modes of fimplifying 

 the hydrometer ; defcription of his own improved hydroe 

 meter : with anfwers to objections that probably might be 

 made to it ; and he concludes with a chapter on the neceflity 

 of a ftandard for proof, and other practical objects of confe- 

 quence in this bufinefs. 



M. Speer's own hydrometer confifts of a ball and ftem, with Defcription of 

 counterpoife beneath as ufual, and the upper or graduated p J er ^/ ro ~ 

 ftem is made of an octagonal form. Upon each of the eight octagonal j each 

 faces is engraved a fcale of per-centages ; by infpection of ide havin S *• 

 which, the quality of the fpirit is feen. But as the inftrument different tempe- 

 will fink to different depths in the fame fpirit, according to r «urc. 



its 



