Prof. Odling on Chemical Notation. 123 



hypobromous acid, whence H*K^O^ (hypothetical 1 vol.) should 

 represent the molecule of potassic water or caustic potash, — 

 -■£- parts of bromine, and ^f- parts of potassium being the chlorous 

 and basylous equivalents of ^ part of hydrogen, and having 

 moreover the same specific heat as one another. Whether or 

 not Gerhardt's view of the molecular ratio of water to caustic 

 potash is correct, I trust I have not failed in making it " ridi- 

 culously clear" that Mr. Waterston's proof of its incorrectness 

 is a transparent fallacy. 



With the exception of a few strange vagaries, inconsistent 

 with the unity of his own scheme, such as halving the accepted 

 combining weight of hydrogen, and not halving that of potas- 

 sium, halving the accepted formula of oxalic ether, C 2 (C 4 H 10 )O 4 , 

 and not halving that of formic ether, C(C 2 H 5 )HQ 2 , &c, I have 

 nothing whatever to say against Mr. Waterston's V.-D. system, 

 because it is neither more nor less than the system of Gerhardt 

 as developed by his followers*. But in Gerhardt's integral 

 notation the smallest proportion of an isolated body is taken as 

 two volumes, and the smallest proportion of a constituent 

 element as one volume; whereas in Mr. Waterston's suggested 

 fractional notation the smallest proportion of an isolated body is 

 taken as one volume, and the usual smallest proportion of a 

 constituent element as half a volume. This mere notational 

 change may be perhaps of the greatest possible importance ; but 

 at present we have only been told and not shown so. 



I am quite at a loss to understand why Mr. Waterston, in re- 

 introducing his long-cherished views to public attention, should 

 not have placed them at once on an independent basis, instead 

 of first going out of his way to make an unfair attack upon me, 

 and then using his attack as a peg on which to hang them. 

 Should he at any time see fit to return to this subject — should 

 he really think that the notions which he conceived some fifteen 

 years ago, and which others had conceived many years before 

 then, are unknown at the present day because in some parti- 



* In ninety-nine cases out of a hundred the vapour-density of a body, 

 elementary or compound, harmonizes thoroughly with its chemical rela- 

 tions. In a few cases one and the same body, elementary or compound, 

 has two distinct vapour-densities, only one of which, and that the least 

 readily observable, harmonizes with its chemical relations; while in another 

 few cases the body, elementary or compound, has a single observed vapour- 

 density which does not harmonize with its chemical relations, and is only 

 believed to have a second hitherto unobserved vapour-density which is in 

 harmony therewith. Thus, in addition to its observed vapour-density of 

 62, phosphorus is believed to have an hitherto unobserved vapour-density 

 of 3\, — 31 parts of phosphorus being the chemical representative of 14 

 parts of nitrogen, the observed vapour-density of which is 14 ; and so in a 

 few other instances. 



