

SCIENTIFIC NEWS, 287 



flandard of proof; of over-proofs and under-proofs, and the Atkins on the 

 modes of appreciating them ; of Mr. Gilpin's experiments of^ufritSoua"'* 

 and tables ; and of the means of adapting them to the prefent liquors, 

 flandard, with various problems and rules for that purpofe ; 

 and concludes with the two tables of the authors mentioned 

 in the title-page. 



The firft chapter treats very perfpicuoufly of the fubject in 

 general, and the intricacy in which it is involved by the joint 

 effects of concentration and change of temperature. 



In the feeond the authors proceed to the eftimation of the 

 ftrength of proof fpirit, as deducible from a loofe paffage in an 

 act of parliament palled in 1762, by which it is enacted, that 

 " for the purpofes of that act, each gallon of brandy or fpirits 

 of the ftrength of one to fix under hydrometer-proof, (hall be 

 taken and reckoned at 7 lbs. 13 oz. the gallon ; and which 

 feems to be the only claufe in the ftatute-book, in which the 

 ftrength of any kind of fpirituous liquor is attempted to be 

 defined by reference to its fpecific gravity. The temperature 

 of the liquor and fome other circumftances are here left to be 

 aflumed, which the authors have accordingly been under the 

 neceffity of doing, and from hence they deduce, that proof 

 fpirit may reafonably be confidered as having the fpecific gra- 

 vity of 920 at 60°. according to the common acceptation j 

 and this they accordingly recommend as the future legal defi* 

 nition of that flandard. 



The third chapter contains a diftinct account of the various 

 modes of comparifon hitherto in ufe, and of their refpective 

 inconveniences and defects. According to the fyftem propofed 

 by the authors, the denomination itfelf would at once indicate the 

 real comparative value of the fpirit in queftion, by reference 

 to the equivalent quantity of proof fpirit, or that which would 

 produce or be producible from 100 gallons of the former, by 

 the addition of water to the ftronger of the two, till they were 

 reduced to the fame degree of ftrength ; allowance being made 

 in all cafes for the concentration which takes place by mixture, 

 and the change in bulk and confequent difference in value by 

 meafure, according to the exifting temperature. Thus, an 

 under-proof of which 100 gallons might be made up "with 

 water from 80 gallons of proof, would be called fpirit of u 80" 

 or * 20 under-proof," and a fpirit of which 100 gallons would 

 when reduced to proof, make 134, would be called ** J 34, 



or i 



