49 
_ Art. V. A Table of Prime Equivalent Numbers, for the 
use of the Chemical Students in the Royal Institution. 
Tut following Table of Prime Equivalents refers to hydrogen 
as unity, and is founded upon.the assumption that the specific 
gravity of hydrogen is to that of oxygen as 1 to 16; 100 cubic 
inches of hydrogen being regarded with Dr. Prout, (Annals of 
Phil., V1., 322.), as weighing, at mean temperature and pres- 
sure, 2.118 grains, and 100 cubic inches of oxygen 33.8 grains; 
water, therefore, composed of two volumes of hydrogen, and 
one volume of oxygen, consists, by weight, of 1 of hydrogen 
and 8 of oxygen. The weight of 100 cubic inches of chlorine, 
at mean temperature and pressure, is assumed as =76.248 gers., 
so that the specific gravity of hydrogen is to that of chlorine as 
1 to 36; these numbers, therefore, will represent the weights 
of the elements of muriatic acid gas, which consists of equal 
volumes of hydrogen and chlorine; and, assuming water to be 
a compound of | prime of hydrogen and 1 of oxygen, and muri- 
atic acid, of 1 prime of hydrogen and 1 of chlorine, the prime 
equivalent of water will be 9, and that of muriatic acid 37. 
The specific gravity of hydrogen, compared with nitrogen, is as 
1 to 14.—100 cubic inches of nitrogen, therefore, will weigh, at 
mean temperature and pressure, 29.65 grains; and its sp, er. 
compared with that of oxygen, will be as 14 to 16. Ammonia 
consists of 3 volumes of hydrogen and 1 of nitrogen, condensed 
into the space of 2 volumes ; so that 100 cubical inches of ammo- 
nia will weigh 18 grs. and, assuming it to consist of 1 prime of 
nitrogen and 3 of hydrogen, its prime equivalent will be =17_ 
It will be observed, from the above instances, that, supposing 
the data correct, oxygen, chlorine, and nitrogen, are represented 
by numbers which are entire multiples of hydrogen, and expe- 
riment bears us out in assuming that all other bodies admit of 
similar numerical representation. The following Tables exhibit 
a series of equivalents, each of which is a whole number, in 
reference to hydrogen as unity, and which, with the aid of the 
sliding-rule, as used in Dr. Wollaston’s scale, will, it is hoped, 
