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Proceedings of the Boyal Society 
also 2, thus agreeing very closely. It is to be remembered, how- 
ever, that these results have been obtained by experiment on the 
eye of the frog, but similar changes have been observed in the eyes 
of mammals. In the latter, however, the amount of alteration is 
not so great, in all probability owing to the rapid death of the parts. 
10. When one clay-point is placed in contact with the cornea or 
nerve, and the other with the section of the optic lobe, a current is 
at once obtained, which is sensitive to light. In this experiment 
the eye is left in the orbit, and the nerve is uninjured. Thus, the 
effect of light on the retina has been traced into the brain. 
The following Gentlemen were elected Fellows of the 
Society 
Donald Crawford, M.A., Advocate, Fellow of Lincoln College, Oxford. 
M. M. Pattison Muir, Esq., Senior Assistant in the Andersonian 
Laboratory, Glasgow. 
Monday , 19 th May 1873. 
D. MILNE HOME, LL.D., Vice-President, in the Chair. 
The following Communications were read 
1. On the Thermal Influence of Forests. By Robert Louis 
Stevenson, Esq. Communicated by Thomas Stevenson, Esq. 
The opportunity of an experiment on a comparatively large 
scale, and under conditions of comparative isolation, can occur but 
rarely in such a science as Meteorology. Hence Mr Milne Home’s 
proposal for the plantation of Malta seemed to offer an exceptional 
opportunity for progress. Many of the conditions are favourable 
to the simplicity of the result ; and it seemed natural that, if a 
searching and systematic series of observations were to be imme- 
diately set afoot, and continued during the course of the planta- 
tion and the growth of the wood, some light would be thrown on 
the still doubtful question of the climatic influence of forests. 
Mr Milne Home expects, as I gather, a threefold result : — 1st, 
an increased and better regulated supply of available water ; 2d, 
an increased rainfall ; and, 3d, a more equable climate, with more 
