224 The Ottawa Naturalist. 



the electrode in straight lines, and is capable of throwing a 

 shadow (of a piece of n:iica, &c.,) surrounded by a brilliant 

 fluorescence. Tubes containing gems, as diamond, ruby, emerald, 

 topaz, etc., were illustrated in this way with most beautiful effect. 

 The rectilinear light is also capable of producing mechanical 

 effects, and these were demonstrated. One ot the most beauti- 

 ful experiments was that in which a tube of potash was fused 

 into a perfectly vacuous globe provided with electrodes. The 

 vacuum acted as a complete non-conductor, but as the potash 

 tube was treated and a little moisture generated, the striae began 

 to appear. As the potash tube cooled, and the moisture was re- 

 absorbed, the phenomena proceeded in reverse order. 



Professor Cox went on to state the theories which have been 

 promulgated to explain the appearances referred to ; but our 

 space will not permit us to attempt any.exposition of these. But 

 it would be inexcusable to omit stating that the whole field 

 opened up by Crooke's and more recently investigated by 

 Lenard, Roentgen and others, is really very imperfectly explored 

 as yet, and may expected to yield rich treasure as research pro- 

 gresses. 



December i/TH, Ottawa Literary and Scientific Society. — 

 " Goether By Prof. Leigh R. Gregor, M.A , Ph.D., (Heidel- 

 berg), of McGill University, Montreal. 



Before introducing the lecturer (Dr. Gregor) to the audience. 

 Mr. O. J. Klotz, who was chairman on this occasion, seized the 

 opportunity and on behalf of the members of the two societies 

 under whose auspices the lecture course was organized, disclaim- 

 ed publicly their having had anything whatever to do with a 

 certain item which had appeared in the daily press of the 

 Capital reflecting upon the suitability of the hall for public 

 lectures. The hall is most eminently fitted and particularly well 

 adapted for courses of free public lectures like these. 



Dr. Gregor's valuable lecture was greatl)- appreciated by the 

 large audience present. 



