358 M. C. Lea on Numerical Relations existing 
6,8 and 9. The values of a were likewise always small, never 
exceeding 8. ‘The values of x were restricted to whole number, 
This view, although new and ‘ingenious, is evidently exposed — 
to a serious objection: the series include too much. The form — 
In the third, oxygen is classed with the nitrogen-phosphorus : 
group, into which antimony only enters with an error of 77." 
tended them. In place of referring his series to the type 
formic acid series alone, he includes the types of substituted ge 
moniums and stannethyls, under the general form ee a ‘ 
t FS 
Prof. Cooke, but restricting it more closely in its ap seer we 
yl é RET ye 
. z term of the other, exhibit a constant difference within a ce 
tain degree of approximation. ~ 
e@ wrote w 
arises from the fact that the equivalent of antimony ae 
f as hi 1, 
be, and by diminishing the value of the variable x corresponding to his term, OY» 
btained. : 
* This probably 
received at the time when Prof. Cook higher than it oe 
& nearer approximation would be o 
