382 
Proceedings of the Royal Society 
And so generally 
( \ \ \ 
K \eq a 2 a 6 . . . . a n J 
= K 
/ 1 b x _&2_ 
\^1 » a 2^ 5 «3& 2 5 <l ib l b 3 > a i 
Ms 
5M 
...X-ib n ^ 
• ■•K-X 
To this may be added the following as being derived in similar 
fashion : — 
K l a 2 x 1 , a.x , a 3 x , ajc .... a n x ^ ^ / = K (eq , a 2 , a 3 ... a n ) 
if n be even, and 
= K (eq , a 2 , a 3 ... a^)x ~ i 
if n be odd. 
The simple continuant I have found to be identical with Euler’s 
11 Novus Algorithmus .” An examination of his paper with this 
title will at once make evident the advantages of the new mode of 
considering the function. 
Monday, 4 th May 1874. 
Sir WILLIAM THOMSON, President, in the Chair. 
The following Communications were read : — 
1. On the Formation of Allotropic Sulphur. 
By James Dewar, Esq. 
2. On Some Compounds of Dimethyl-Thetine. By Professor 
Crum Brown and Dr E. A. Letts. 
( Abstract .) 
In this paper the authors describe in detail compounds of 
dimethyl-thetine, some of which were enumerated in an earlier 
communication. Hydrobromate of dimethyl-thetine is readily 
obtained as a colourless crystalline body by the action of sulphide 
of methyl on bromacetic acid at ordinary temperatures. Its analysis 
shows that it contains quantities of the different elements agree- 
