CHEMICAL AND PHARMACEUTIC MANIPULATIONS. 113 
Thus the analysis of blue vitriol, by Berzelius gives the 
following numbers in the 1st column, expressed in 100 
parts. 
Oxide of copper 32.13 0.803 1.018 1 
Sulphuric acid 31.57 0.789 1.000 1 
Water 36.30 4.0333 5.111 5 
" The constituents being severally divided by their com- 
bining weights, the numbers in the 2d column result; and 
by dividing each of these by 0.789, we get the 3d column, 
which, by making a slight allowance for the imperfections 
of analysis, gives the proportions between the equivalents 
1:1:5. 
" Having determined the number of equivalents, a for- 
mula is easily established, which in the case of carbonate of 
lime is CaO,C0 2 , and of blue vitriol CuO,S0 3 +5HO. Now 
the per centage composition of dry or anhydrous sulphate of 
copper is 50 oxide of copper and 50 sulphuric acid. If we 
compare it with the per centage composition of blue vitriol, 
the relation between them is not readily seen ; and in the 
case of many other substances, no relation whatever can be 
detected; but if the formulas deduced from each analysis be 
compared, their relation is at once evident, for we perceive 
that the blue vitriol contains 5 equivalents of water, which 
the other does not, and that otherwise they are one and the 
same substance. 
" The silicates form a numerous class of crystallized 
minerals, whose formula may be established by the forego, 
ing method, or by determining the quantity of oxygen in 
each element, and bringing these quantities into whole 
numbers, those of the isomorphic bases being added 
together. It is, perhaps, a more convenient method for 
these bodies than the preceding. 
The construction of the formula for an organic body de- 
pends on precisely the same principles, and is ascertained 
by a similar process; but there is a peculiarity in the for- 
mula of organic bodies, which is rarely met with in mineral 
10* 
