534 PROCEEDINGS OF THE SOCIETY. 



scribed by Professor Hickson from the ' Discovery ' collection. The 

 President went on to give a brief description of the four species, and said, 

 in conclusion, that he felt it a privilege to share, even in this very in- 

 direct way, in the work of an expedition which had reflected so much 

 credit on every one concerned. 



Mr. James Murray said the Alcyonarians were a group which he knew 

 very little about, but he had been very much interested in hearing Pro- 

 fessor Thomson's remarks. He collected the material in whjch the 

 specimens were found, but he was fortunate enough to secure the services 

 of a very good marine biologist, Mr. Pearcey, who picked out the speci- 

 mens, and got Professor Thomson to examine them. It was not ex- 

 pected they would lie likely to get anything very different from what the 

 ' Discovery ' people got. He quite agreed with the President's remarks 

 about the appetite for new species. 



The President enquired how they managed to get delicate forms like 

 Ceratoisis delkatula in such good condition. 



Mr. Murray said they did not find any difficulty in preserving them, 

 and took no particular precautions. Some were put into spirit and some 

 were in formol. 



The President said he noticed some of the specimens were in formalin, 

 but this was a bad medium, as it had a slow corroding and eventually 

 solvent effect on the spicules. 



Mr. Heron-Allen was glad to have the opportunity of proposing a 

 vote of thanks to the President for his very interesting communication. 

 The President had spoken of the privilege he felt it to be to have had 

 these specimens placed in his hands for examination, but he thought the 

 Society should congratulate itself upon having so distinguished a biologist 

 at their head that they were afforded the opportunity of having these 

 interesting objects submitted to them at the earliest opportunity. He 

 had great pleasure in proposing a very hearty vote of thanks to Professor 

 Thomson for bringing these Arctic Alcyonarians before the Society. 



The motion was unanimously carried by acclamation. 



Dr. Hebb read a paper by Mr. E. M. Nelson, " On an Apparatus for 

 Increasing the Power of an Achromatic Condenser." 



Mr. Conrady has supplied the following considered account of his 

 impromptu remarks : — 



If Mr. Nelson expects to obtain a more brilliant flame-image by the 

 addition of the doubly-reflecting glass ring he will certainly fail, for this 

 would be directly contrary to the second law of thermodynamics. When 

 Clausius first definitely stated this famous law, "That heat cannot be 

 transferred from one body to another warmer than itself without a com- 

 pensating expenditure of energy," doubts were expressed whether radiant 

 heat— and therefore also light — did not form an exception ; in other 

 words, whether it was not possible by suitable lenses and mirrors to form 

 an image more brilliant than the object itself. Clausius proved to every- 

 body's satisfaction that this was impossible : that the best result possible 

 was an image of the same intrinsic brilliance as the object, and that this 

 was obtained with any corrected optical system which also fulfilled the ' 

 sine-condition — of which latter Clausius was another early discoverer. 



