203 RehfJon lefivcen the Sperijic Gravities and 



curacv of the above dtfiniiion. The weight of the averdu- 

 pMS pound, and the Icngtli of the inch ana consequent soHd 

 content of the wine-gallon, neither of which was at the time 

 of making the statute appreciated with sufficient accvu-acy, 

 we shall for the present take to be so, and assume that the 

 former is equal to 7000 grains troy ; and that the general 

 niation between the measures and weights of this country 

 is sucli, that the cubic inch of distilled water, at Oo'^'of Fah- 

 reulieit's thermometer, would weigh, in air at the same tem- 

 perature when the barometer stands at 29\, 2.32^ of the same 

 grains. [Fz-it' vol. xv. p. 278.] There still remain, however, 

 two very important questions which require to be answered 

 before we c:in ascertain tlie real strength of proof spirit. 



latly, What is meant by one to six under proof? Is it in- 

 tended to signify that compound which would be produced 

 by the addition of one part of water to six of proof spirit by 

 Bieasure — or thai of which a given quantity by measu.c- shall 

 contain and consequently be equal in value to six-sevenths 

 of tkat Vieasurc of proof spirit ? These are by no means 

 tonvertiblc terms, as will be easily perceived bv considering 

 v'hat is before mentioned in § 10. We must take one sup- 

 positio'i or the other ; and wc shall, for tiic reasons which are 

 stated hcvtaiter in § 24, adopt the latter. 

 . *2div, W^hat is the temperature at wluch it is intended that 

 this spirit should weigh seven pounds thirteen ounces ? A 

 compound of this strength would vary in its \\ eieht upwards 

 of two ounces per gallon in difterent temperatures in this 

 climate, and still more in some other couiitrics ; and every 

 liquor of wiiieh a gallon a', any possible temperature would 

 be of that weight, would answer equally to the description 

 of the statute. A compound apparently 12 percent, under 

 proof at 35°, would, if judged of by this criterion, appear to 

 be over proof at 70°; and vice versa. 



§ 17. The omission to fix the temperature, therefore, at 

 whicii the compound mentioned in the statute is to weigh 

 seven pounds thirteen ounces per gallon, coupled with the 

 circuity of describing a mixture differing from proof strength 

 Father fhan proof spirit itself, and from which the strength 

 of the latter can only be determined by a calculation in which 

 difi'erent data mav be assumed, are the leading causes of all 

 the uncertainly relative to this subject. Something must be 

 guessed at with respect to each; and the follouing is the 

 Hiode in which the authors of this work have hitherto pro- 

 ceeded in the appreciation of the strength of proof spirit. 



Assuming that tlie avoirdupois pound and the content of 

 the wine-gallon of 231 cubic inches bear such, a relation to 



each 



