of Edinburgh, Session 1885-86. 
655 
5. On the Nature of the Relationship of Urea-Formation of 
Bile Secretion. By D. Noel-Paton, M.B., C.M. # 
6. Note on the Collisions of Elastic Spheres. By Pro- 
fessor Tait. 
{Abstract.) 
In my paper of January 18th {ante, p 537) I had assumed all 
directions of the line of centres at impact to he equally probable. 
The introduction of the true condition affects the average value of 
w 2 - uv 
by a numerical factor only ; so that the proof of Maxwell’s Theorem 
remains valid. The expressions for the separate average values of 
u 2 and of uv, however, are altered more profoundly* 
PRIVATE BUSINESS. 
Sir William Thomson gave notice of the following Motion, to 
be considered as part of the Private Business on the evening of 
19th April: — “That henceforth the Meetings of the Royal Society 
be held in the Afternoon instead of at 8 p.m.” 
Mr John Murray gave notice of an Amendment to the Motion of 
Sir William Thomson, in the terms, “ That the First Meeting in 
each Month take place at 4 p.m.” 
* This paper appears in full in the Journal of Anatomy and Physiology, voh 
xx. p. 520, 1886. 
