10 RECENT CHANGES IN CHEMICAL NOTATION AND ATOMIC WEIGHTS. 
Water— 
0 , 
( 
c 2 o 2 
Ho 
I may be allowed to say that, as it appears to me, this system is open to very 
important objections. In the.first place it has been very properly maintained 
that the mind has naturally more than sufficient tendency to materialize in 
surveying questions connected with the manifestation of chemical force with¬ 
out being propelled in the same direction by the constant employment of 
pictorial formulae. The lines connecting the atoms in such formulae, we have 
reason to believe, have no more real existence in nature than the epicycles and 
deferents of ancient astronomy. Of course this is plainly set down by those 
who employ graphic notation, but I conceive a system requiring perpetual 
protestation to be little adapted for the purposes of teaching. What advantage 
can it have, then, since constitution can be as well expressed by letters alone? 
The system, too, has some difficulties in application. Polyatomic elements, it 
is well known, do not exhibit invariably the same atomicity ; when, for ex¬ 
ample, phosphorus is combined with five atoms of Cl it is quite saturated ; but 
it also combines with Cl 3 ; what, in that case, becomes of the two units of com¬ 
bining power which are not exercised ? It has been thought necessary to 
invent the follow ing account of them, that the tw r o ‘ bonds ’ become latent by 
uniting w r ith and saturating each other! 
This extraordinary idea was not hit upon till graphic formulse came in vogue- 
Little need be suggested as to the inconvenience occasioned by the trouble 
of writing these diagrams, and the space they occupy; but it might be 
pointed out that enthusiasm, no doubt, in the cause has led to the represen- 
