on Spirituous Liquors . 
loaded with confiderable weights, has been given in the XXXlIId 
volume of the Journal de Pbyjique. 
I muft not conclude this part of the Report without ob- 
ferving, that as the experiments were made with pure ipirk 
and water, if any extraneous fubftances are contained in the 
liquor to be tried, the fpeciiic gravity in the tables will not 
give exactly the proportions of water and fpirit in it. The 
fubftances likely to be found in fpirituous liquors, where no 
fraud is fufpedted, are, eflential oils, lb me times empyreumatic, 
mucilaginous or extradlive matter, and perhaps fome faccha- 
rine matter. The efFedt of thefe, in the courfe of trade, 
feems to be hardly fuch as would be worth the cognizance of 
the excile, nor could it ealily be reduced to any certain rules. 
Eflential and empyreumatic oils are nearly of the fame fpecific 
gravity as fpirit, in general rather lighter, and therefore, not- 
withftanding the mutual penetration, will probably make little 
change in the fpecific gravity of any fpirituous liquor in which 
they are difloived. The other fubftances are all heavier than 
fpirit; the fpecific gravity of common gum being 1,482* 
and of fugar 1,606, according to the tables of M. Brisson. 
The effedt of them therefore will be to make fpirituous liquors 
appear lefs ftrong than they really are. An idea was once en- 
tertained of endeavouring to determine this matter with fome 
preciflon; and accordingly Dr. Dollfuss evaporated 1000 
grains of brandy, and the fame quantity of rum, to drynefs ; 
the former left a reliduum of 40 grains, the latter only of 8 f 
grains. The 40 grains of refiduumfrom the brandy, difloived 
again in a mixture of 100 of fpirit with 50 of water, in- 
creafed its fpecific gravity ,00041 ; hence the effedl of this 
extraneous matter upon the fpecific gravity of the brandy con- 
taining it would be to increafe the fifth decimal by 6 nearly, 
equal 
