270 On the. Analysis of Organic Substances. {Ocr, 
shown that it holds equally good with respect to them, with some 
slight modifications only, as with inorganic compounds.* His ad- 
mirable paper on this subject: has thrown a new light on the consti- 
tution. of natural objects, and at the same time opened a field of in- 
vestigation no. less difficult than interesting. My object at present is 
chiefly to point out the important assistance which may be derived 
in similar researches from the use of the invaluable scale of chemical 
equivalents contrived by Dr. Wollaston; a fact well known to its 
distinguished author, and’many others; but which, perhaps; is not 
go generally so as it ought to be. On the supposition. that this instru- 
ment be correct, or nearly so, which no one can doubt, and that 
organic substances be really formed on the principles of definite 
proportions, we are enabled by its means to approximate in most 
instances, with almost absolute certainty, to the number of atoms 
of each element entering into the composition of a ternary or qua- 
ternary compound. The data requisite for this purpose are, 1. ‘The 
knowledge of the proportions of at least two of the elements enter- 
ing into an organic compound; and, 2. The knowledge of the 
weight of its atom, or some multiple of it. Of these two, the first 
is by far the most-important ; the second is not absolutely necessary. 
To render this seate adapted for our purpose, it is only necessary 
to extend it a little, which may be conveniently done by pasting two 
slips of drawing paper on its edges, which must be of such a breadth 
as just to lap over and cover the margins containing the names of 
the chemical substances, and to coincide with the graduated edges 
of the slide. On these slips of paper are then to be marked the 
multiples of an atom of oxygen, hydrogen, and carbon, from one 
to ten; and of azote, from one to four or five, or more. Thus 
prepared, it will be fit for our use; and to those who are unac- 
qguainited with the principles of the instrument, the following éx- 
amples will show the mode of applying it : to others these examples 
will be probably unnecessary. 
. Example 1.—Suppose we had found the weight of a particle of a 
ternary compound to be 46°5, oxygen being 10, and that 46°5 parts 
of it contained 15°15 carbon, 1°34 hydrogen, and consequently 
30°01 oxygen. ‘To find the number of atoms of each of these 
elements, we have only to place 10 on the slide opposite oxygen; 
and then opposite each of the numbers respectively we have the 
number of atoms of each element required. Thus apposite 15°15 
carbon, we have 2 carbon; opposite 1°34 hydrogen, 1 hydrogen ; 
and opposite 30°01 oxygen, 3 oxygen. Such,a compound, then, 
will consist of three atoms oxygen, two atoms carbon, and one atom 
hydrogen. 
Again: supposing we were ignorant of the weight of an atom of 
this ternary compound, but had found that 100 parts of it contained 
32:4 carbon, 2 8 hydrogen, and consequently 64°38 oxygen ;° to find 
the number of atoms of edch element in this case we have only to 
; Tet: | 
* See Annals.of Philosophy, yol, iy. p. 323, et sequent. ) 0) eel 
