RECORDS • 121 



American Journal of Science for October, 1900. Mr. Parker 

 stated that by this method it seemed possible to measure re- 

 sistances as great as 1,000,000,000 megohms while by the 

 methods at present in common use the practical limit was stated 

 to be about 100,000 megohms. The author gave the results 

 of a series of measurements made on a new form of standard 

 high resistance devised by Professor Rood. This form of 

 standard consists of oxide of manganese on cobalt glass. It 

 gives a convenient means for obtaining resistances of from one 

 to ten thousand megohms. Most of the measurements were 

 for the purpose of determining the best protective insulating 

 material with which to coat the above resistances. The author 

 stated that the work was still in progress. 



The first paper by Professor J. K. Rees gave an outline of the 

 present classification of variable stars and a history of the dis- 

 covery of the new star in Perseus. A number of the theories 

 to account for the phenomena was given and commented upon. 



In the discussion of the paper, Mr. 0. A. Post inquired con- 

 cerning the evidently rapid transformations of energy taking 

 place in the temporary star. Dr. W. S. Day suggested as a 

 possible explanation the retransformation of much of the kinetic 

 energy of the vibrating atoms into gravitational potential energy 

 by the sudden expansion of the matter after collision. 



The second paper by Professor Rees consisted of an exhibi- 

 tion of some very beautiful photographs of nebulae which the 

 Columbia Observatory had lately received from Mr. W. Camp- 

 bell, the director of the Lick Observatory. 



The photographs were taken by the late Dr. J. E. Keeler and 

 an enthusiastic tribute was paid to him for his remarkably suc- 

 cessful work in this field. 



The photographs exhibited were : 



1. Orion nebula, taken November 16, 1898; exposure 40 

 minutes. 



2. Orion nebula, taken December 1 1,1899 j exposure I hour. 



3. 51, M, Cannea Venaticarum, taken May 10, 1899. 



4. Dumb-bell nebula in Velpecula taken July 31, 1899 ; ex- 

 posure 3 hours. 



