1022 



SCIENCE. 



[N. S. Vol. XI. No. 287. 



quadratic involutions and the transforma- 

 tion of elliptic integrals. (2) The repre- 

 sentation of a number as the sum of two 

 squares. (3) The twisted biquadratic curve 

 of the first species. 



Electrical Screening in Vacuum Tubes : By J. 

 C. McLennan, B.A., Demonstrator in 

 Physics, University of Toronto. Com- 

 municated by President Loudon. 

 The paper deals with a changing effect 

 observed by Professor J. J. Thomson in 

 connection with his experiments on Faraday 

 cylinders inserted in vacuum tubes. The 

 effect referred to is traced to electric con- 

 duction along the surface of the glass walls 

 of the tube. Insulators such as sealing 

 wax are shown to be quite unreliable in 

 electrometric work without inner tubes 

 when voltages such as those produced hy an 

 induction coil are used. The importance 

 of good earth connections is developed and 

 Faraday cylinders inserted in vacuum tubes 

 are shown to act as perfect electrical screens 

 unless made of metal thin enough to permit 

 cathode rays to pass through. 



Canadian Experiments with Nitragin for j^i'o- 

 moting the Choivth oj Legumes : By Feank 

 T. ShutTjM.A., F.LC, F.C.S., and A. T. 

 Chaeeon, B.A. 



By means of diagrams and photographs 

 Mr. Shutt indicated the striking results 

 recently obtained at the Central Experi- 

 mental Farm or Station at Ottawa in soil- 

 inoculation. The paper when published 

 will be copiously illustrated. Fellows of 

 Section IV. attended the meeting in Sec- 

 tion III. during the reading of this impor- 

 tant paper. 



An Apparatus for the Determination of the Melt- 

 ing Point of Fats : By Feank T. Shutt, 

 M.A.,F.I.C., F.C.S., and H. W. Chabl- 

 TON, B.A., Sc. 

 On Soil Temperature: A continuation of 

 papers presented at preceding meetings. 

 By Prof. C. H. McLeod, M.E. 



GEOLOGICAL AND BIOLOGICAL SCIENCES. 



2716 Nepheline Rocks of Ice River, B. C : By 

 A. E. Baelow, M.A., D.Sc. Communi- 

 cated by Dr. G. M. Dawson. 

 Among the rock specimens collected by 

 Dr. G. M. Dawson, in 1884, are some which 

 seem to possess many points of rather un- 

 usual interest at the present time, illustra- 

 tive for the most part of the phenomenon 

 of magmatic differentiation, with which of 

 late we have become more familiar through 

 the labors of Vogt, Brogger and others. 

 The specimens in question were obtained 

 from exposures along and in the vicinity of 

 Ice Eiver, a branch of the Beaverfoot River 

 in British Columbia, about eight miles 

 southeast of Leanchoil and Ottertail sta- 

 tions on the Canadian Pacific Railway. 

 The hand specimens, which were made the 

 subjects of examination, were of necessity 

 rather hurriedly collected and were chosen 

 mainly as representing the various phases 

 of this igneous complex. It is therefore a 

 very agreeable surprise to find that the 

 material thus selected at a time when 

 magmatic differentiation was but little 

 understood, should illustrate a passage so 

 complete that no appreciable gap occurs 

 unrepresented by specimens from the most 

 basic Ijolite containing 36.9SS per cent, of 

 silica to ordinary nepheline and sodalite 

 sj^enite containing 53.638 per cent, of silica. 



Notes on North American Species of Dadoxylon : 

 By Peofessoe D. P. Penhallow, of Mc- 

 Gill University. 



The author brings under review a large 

 amount of material collected by the late 

 Sir William Dawson, representing various 

 species of the genus Dadoxylon, and he also 

 describes new species of allied plants from 

 the Cretaceous and Permian of Kansas from 

 the collections of Professor C. S. Prosser. 

 The plants formerly included under the 

 name of Dadoxylon, are now to be regarded 

 as falling into the three principal groups, of 



