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Remarks on Variation in Animals and Plants. To accompany the first 

 Report of the Committee for conducting Statistical Inquiries into the 

 Measurable Characteristics of Plants and Animals. By Professor W. 

 F. R. Weldon, F.R.S 379 



The Effect of Environment on the Development of Echinoderm Larvse : 

 an Experimental Inquiry into the Causes of Variation. By H. M. 

 Vernon, B.A 382 



List of Presents 385 



No. 345. March 7, 1895. 



List of Candidates 386 



The Rubies of Burma and Associated Minerals their Mode of Occur- 

 rence, Origin and Metamorphoses. A Contribution to the History of 

 Corundum. By C. Barrington Brown, Esq., F.G.S., and J. W. Judd, 

 F.R.S., F.G.S., Professor of Geology, Royal College of Science 387 



The Action of Heat upon Ethylene. II. By Vivian Lewes, Professor 

 of Chemistry at the Royal Naval College, Greenwich 394 



On the Measurement of Pressures by the Crusher-Gauge. By W. 



Kellner and W. H. Deering 404 



List of Presents Mi . 410 



March 14, 1895. 



Croonian Lecture. On the Nature of Muscular Contraction. By Th. 

 W. Engelmann, Professor of Physiology in " the University of 

 Utrecht .*. 411 



List of Presents 433 



March 21, 1895. 



On the Diselectrin cation of Air. By Lord Kelvin, P.R.S., Magnus 

 Maclean, M.A., F.R.S.E., and Alexander Gait, B.Sc., F.R.S.E 436 



On the Conditions affecting Bacterial Life in Thames Water. By E. 

 Frankland, D.C.L., F.R.S 439 



The Cause of Luminosity in the Flames of Hydrocarbon Gases. By 

 Vivian B. Lewes, Professor of Chemistry at the Royal Naval College, 

 Greenwich 450 



A possible Explanation of the two-fold Spectra of Oxygen and 

 Nitrogen. By E. C. C. Baly, A.I.C., 1851 Exhibition Scholar in Uni- 

 versity College, London 468 



On the Question of Dielectric Hysteresis. By Alfred W. Porter, B.Sc., 

 Demonstrator of Physics, University College, London, and David K. 

 Morris, 1851 Exhibition Scholar, University College, London 469 



On the Chpnges in Movement and Sensation produced by Hemisection 

 of the Spinal Cord in the Cat. By Charles Devereux Marshal], 

 F.R.C.S 475 



On the Analysis of Voluntary Muscular Movements by certain new 

 Instruments. By William R. Jack, M.D., B.Sc 477 



