IX 



Page 



On the Organization of the P ossil Plants ot the Coal-measures. — Part V. 

 Asterophyllites. By W. C. Williamson, F.R.S., Professor of Natural 

 History in Owens College, Manchester 394 



On a tendency observed in Sun-spots to change alternately from the one 

 Solar Hemisphere to the other. By Warren De La Rue, D.C.L., F.R.S., 

 Balfour Stewart, LL.D., F.R.S., and Benjamin Loewy, F.E.A.S 399 



On the Structure and Development of the Skull in the Pig (Sus scrofa). 

 By W. K. Parker, F.R.S . 402 



Results of the Comparisons of the Standards of Length of England, 

 Austria, Spain, United States, Cape of Good Hope, and of a second 

 Russian Standard, made at the Ordnance Survey Office, Southampton. 

 By Lieutenant- Colonel A. R. Clarke, C.B., R.E., F.R.S., &c, under the 

 direction of Major-General Sir Henry James, R.E., F.R.S., &c, Director- 

 General of the Ordnance Survey. With a Preface and Notes on the Greek 

 and Egyptian Measures of Length by Sir Henry James 407 



Researches on Emeralds and Beryls. — Part I. On the Colouring-matter of 

 the Emerald. By Greville Williams, F.R.S 409 



No. 146.— June 19, 1873 (continued). 



On a Standard Voltaic Battery. By Latimer Clark, C.E 422 



Note on High-Power Definition as illustrated by a compressed Podnra- 

 scale. By E. B. Beaumont, F.R.S., and Dr. Royston-Pigott, F.R.S 422 



On the Accommodation of Vision, and the Anatomy of the Ciliary Body. 

 By Arthur Trehern Norton, F.R.C.S., Lecturer on Anatomy at St. Mary's 

 Medical School 423 



On Mr. Spottiswoode's Contact Problems. By W. K. _ Clifford, M.A., 

 Professor of Applied Mathematics and Mechanics in University College, 

 London 425 



Observations on the Functions of the Ganglia which are formed in the 

 Posterior Roots of the Spinal Nerves. By Robert Lee, M.D., F.R.S 426 



Researches in Circular Solar Spectra, applied to test Residuary Aberration 

 in Microscopes and Telescopes, and the construction of a Compensating 

 Eyepiece, being a sequel to the paper on a Searcher for Aplanatic 

 Images. By G. West Royston-Pigott, M.A., M.D. Cantab., Memb. 

 Rojr. Coll. Phys., Fellow of the Camb. Phil. Soc, the Royal Ast. 

 Society, &c, and late Fellow of St. Peter's Coll., Cambridge 426 



On Comparative Vegetable Chromatology. By H. C. Sorby, F.R.S 442 



On the Action of Electricity on Gases. — No. H. On the Electric De- 

 composition of Carbonic-Acid Gas. By Sir B. C. Brodie, Bart., D.C.L., 

 F.R.S., late Waynflete Professor of Chemistry in the University of 

 Oxford 483 



List of Presents 485 



