CHEMICAL NOTATION AND ATOMIC WEIGHTS. 
529 
mation into glycol, and the products of the substituting action ot chlorine de¬ 
monstrate that this body has a replacing value double that of h} r drogen, of 
silver, or of any other monatomic elementary radicle. Wurtz then com¬ 
pared the oxide of ethylene with those of Ba, Sr, Ca, Mg, Mn, Fe, Zn, Pb, 
Hg, etc., showed the similarity of their reactions, and also how, if the atomic 
w eights ot these metals be allowed to be doubled, the general formulae repre¬ 
senting all their compounds might be expressed upon the same types. 
There is one class of compounds, the existence of which fortunately gives 
greater probability to these views than they would otherwise enjoy ; it is 
those remarkable bodies in which the metal is bound up in the same molecule 
with two distinct monatomic radicles. The constitution of these bodies 
favours the idea of the diatomicity of the metals from which they are de¬ 
rived in a similar manner, and to the same extent that the double ethers sup¬ 
port the duplication of the atom of oxygen. 
Monacetic Glycol. 
* (C 2 H 4 )"- 
“ ; o, 
H~ 
c 2 h 3 o 
So-called bibasic 
Basic Nitrate of 
Acetate of Lead. 
Lead of Pelouze. 
Pb" h 
Pb" ■) 
c 2 h 3 o [ 0 2 
NO, 0 2 
H 3 
H 3 
Diacetic Glvcol. 
(CoF 4 )") 
c 2 h 3 o o 
c 2 h 3 o j 
Acetate of Lead. 
Pb" ■) 
c 2 h 3 0 o : 
C 2 H 3 oj 
Nitrate of Lead. 
Pb"h 
N 0 2 [ 0 2 
no;] 
Aceto-butyrie Glycol, 
etc. 
( 0 2 H 4 )") 
c 2 h 3 o 
c 4 h 7 oJ 
Acetonitrate of Strontium, 
etc. 
Sr" ■) 
c 2 h 3 o o 
no 2 3 
Acetonitrate of 
Barium. 
Ba" h 
C 2 H 3 0 [ 0 2 
js t o 2 3 
One other circumstance might be brought forward to help out the same 
side of the argument. Potassium and sodium are undoubted univalent 
radicles. In the compounds which they form with dibasic acids they in¬ 
variably replace the basic hydrogen of these acids one-half at a time. Thus 
we have two sulphates and two tartrates of potassium. 
Acid Sulphate of Potassium . . . P1KS0 4 
Normal salt.K 2 S0 4 
Acid Tartrate of Potassium . . . KHC 4 H 4 0 6 
N eutral Tartrate.K 2 C 4 H 4 O e 
Barium and calcium, and the rest of the metals wFich now figure as di¬ 
atomic, usually furnish with these acids but one salt of the ordinary structuref, 
and the reason of this is obvious : they cannot displace one atom of hydrogen 
alone, and therefore cannot form compounds analogous to the acid sulphates, 
tartrates, oxalates, carbonates of the alkali metals. 
I have thus disposed first of the suggestions derived from a survey of 
strictly chemical phenomena, because I consider that they ought to hold the 
first place in the estimation of the chemist. The physical peculiarities of the 
elements, to which I shall now refer, are of course intimately bound up with 
these, but, although affording strong and acceptable support, ought not to be 
made to take precedence of them. 
Many years ago Gay-Lussac made known the important fact that when. 
* C = 12. 0=16. • 
t There are other compounds, like Turpith Mineral, Hg 4 S 0 4 0 2 , the existence of which is of 
no importance to the argument. 
VOL. IX. 2 M 
