292 
The following Donations to the Library were announced 
London University Calendar. 1860. 8vo. — From the Univer- 
sity. 
Journal of the Proceedings of the Linnean Society. Yol. IY. 
No. 16. 8vo. — From the Society . 
Bulletin de la Societe des Sciences Naturelles de NeuchateL Tome 
V. Part I. 1859. 8vo. — From the Society. 
Maps of Indian Survey. — From the Government of India. 
On a New Method of Measuring Watch-Glasses. By Alexander 
Bryson, F.R.S.E. 1860. 8vo. — From the Author. 
Almanaque Nautico para 1861, Calculado de Orden de S. M. en 
el Observatorio de Marina de la Ciudad de San Fernando. 
Cadiz, 1859. 8vo. — From the Observatory. 
The Canadian Journal of Industry, Science, and Art. January, 
1860. 8vo. — From the Canadian Institute. 
Maps, Sections, and Descriptions of the Geological Survey of Great 
Britain. — From the Director-General of the Survey. 
Account of the Illness and Death of Dr William Pulteney Alison. 
By Patrick Newbigging, M.D., F.R.C.S. — From the Author. 
Monday , 5th March 1860. 
Dr CHRISTISON, Yice-President, in the Chair. 
The following Communications were read : — 
1. On the Utmost Horizontal Distance which can be Spanned 
by a Chain of a given Material. By Edward Sang, Esq. 
The method of investigation followed in this paper for finding the 
limit for a uniform chain, is to suppose a multitude of catenaries all 
having a common vertex, and to take, in each of them, that point at 
which the tension is fixed. The curve passing through all of these 
points has for its equation — 
z — s (1 —sin $), 
x — s . sin & . nep log cot — , 
in which s is the tension, z the vertical, and x the horizontal ordi- 
nate. 
