MANUFACTURE OF WOOD-NAPHTHA. 
49 
The following table is by M. Deville, with a view to show the 
per centage of real spirit in naphtha of different specific gravities at 
the temperature of 48° 5 Fahr. 
Quantity of Water. Specific Gravity. 
00 per cent 0.8070 
10 " 0.8371 
20 " 0.8649 
30 " 0.8873 
40 " 0.9072 
50 « 0.9232 
60 " 9429 
70 " 0.9576 
80 " 0.9709 
90 " 0.9751 
95 " 0.9857 
" If," says M. Deville, " these results are brought to a tempera- 
ture of 60° Fahr., it will be found that there is an almost entire 
correspondence between alcohol and wood spirit, and that the lat- 
ter equally with the former shows a maximum of contraction, which 
always takes place on the combination of one part of wood spirit 
with three of water, that is to say, in a mixture containing 45.75 
per cent, of water. Dr. Ure has also constructed a table of the spe- 
cific gravities of mixtures of wood spirit and water ; but he has 
given 0.8136 as the specific gravity of anhydrous wood spirit, at a 
temperature of 60<> Fahr." In an article on Pyroxylic Spirit and 
its compounds, which appeared in Thompson's Records of Science, 
vol. ii., page 374, it is stated, " the lowest specific gravity, to which, 
as far as we are aware, it has been brought in this country, is 
0.812. Dumas, however, states that its density at the temperature 
of 68° is 0.798, and that of its vapor 1.120. Its boiling point, 
according to the same authority, is 151|°, at a pressure of 30 
inches. Mitscherlich gives 0.798 as its specific gravity, and 180° 
Fahr. as the boiling point. Mr. Scanlan, in the Proceedings of the 
British Association, 1835, gives .828 as the specific gravity, and 
150° as the boiling point. " Wood spirit of 0.870 specific gravi- 
ty," says Dr. Ure, " boils at 144° Fahr., and if it be brought by 
distillation to specific gravity 0.832, it boils at 140° Fahr." The 
commercial wood spirit varies very much both as to its specific 
gravity and its power of dissolving gum sandrac, shellac, &c, from 
its containing acetone, mesite, &c, in variable proportions. The 
presence of these bodies is to be accounted for by the variation in 
the modes employed for obtaining and purifying the wood spirit, as 
5 
