354 Proceedings of Royal Society of Edinburgh. [sess. 
Monday , 1st June 1891. 
Professor Chrystal, LL.D., Yice-President, in the Chair. 
The following Communications were read : — 
1. The Yiolet of the Solar Spectrum. By C. Piazza Smyth, LL.D., 
F.R.S.E. 
2. On the Fossil Plants of the Kilmarnock, Galston, and Kilwinning 
Coal Field, Ayrshire. By Robert Kidston, F.R.S.E., F.G.S. 
3. On Some Relations between Magnetism and Twist. Parts II. and 
III. By C. G. Knott, D.Sc., F.R.S.E., Professor of Natural Philosophy 
in the Imperial University of Tokyo, Japan. T. xxxvi. 485. 
4. The Winds of Ben Nevis. By R. T. Omond, F.R.S.E., Super- 
intendent of Ben Nevis Observatory, and Angus Rankin. T. xxxvi. 
5. On the Blood of the Invertebrata. By Dr A. B. Griffiths, F.R.S.E., 
F.C.S., &c. P. xviii. 288. 
Monday , 15th June 1891. 
T. B. Sprague, Esq., M.A., in the Chair. 
The following Communications were read : — 
1. A Case of Defective Endochondral Ossification in a Human Foetus. 
By Johnson Symington, M.D., and Henry Alexis Thomson, M.D. 
P. xviii. 271. 
2. The Alkaline and Acid Salts of the Blood and Urine, and especially 
those of Phosphoric Acid. By John Berry Haycraft, M.D. 
3. On an Optical Proof of the Existence of Suspended Matter in 
Flames. By Sir George G. Stokes, Bart., F.R.S. (In a letter to Prof. 
Tait.) P. xviii. 263. 
4. Observations on Vegetable and Animal Cells ; their Structure, 
Division, and History. Part II. By J. M. Macfarlane, D.Sc. 
5. A Comparison of the Minute Structure of Plant Hybrids with that 
of their Parents, and its Bearing on Biological Problems. (Illustrated 
by three Parallel Lantern Demonstrations.) Part II. By J. M. 
Macfarlane, D.Sc. 
Monday , 6th July 1891. 
The Hon. Lord M‘Laren, LL.D., Yice-President, in the Chair. 
The following Communications were read : — 
1. On the Solid and Liquid Particles in Clouds. By John Aitken, 
F.RS. T. xxxv. 313. 
2. A Demonstration of Lagrange’s Rule for the Solution of a 
Linear Partial Differential Equation ; with some Historical Remarks on 
Defective Demonstrations hitherto Current. By Professor Chrystal, 
LL.D. T. xxxvi. 
