2/6 REPORTS ON INVESTIGATIONS AND PROJECTS. 



minations of the numerous series of bands contained in their spectra when 

 excited at the temperature of Hquid air. Prehminary experiments have also 

 been made looking to the production of a series of phosphorescent com- 

 pounds having aluminum oxide as their basis, and apparatus for this work 

 has been purchased and installed. 



Mr. H. E. Howe has continued his development of photographic methods 

 for the quantitative determination of the distribution of energy in banded 

 spectra with special application to fluorescence and phosphorescence and has 

 begun the measurement of the fluorescence bands and absorption bands of 

 fluorescein, tetrachlor fluorescein, eosin, and tetrachlor eosin. These sub- 

 stances have been recently prepared in great purity by Prof. W. R. Orndorfif, 

 to whom we are indebted for the opportunity of studying their spectra. In 

 these measurements Mr. Howe is using a photo-electric cell to determine the 

 intensity of the light transmitted by different portions of the photographic 

 plate, as recently described by Professor Merritt and myself in a paper 

 before the American Physical Society (Physical Review, xxxiv, p. 475). 



Mr. G. E. Thompson has been further engaged in the investigation of 

 photo-electric effects in cells having a fluorescent electrolyte, and Mr. T. B. 

 Brown has continued his studies of kathodo-luminescence. 



Mr. C. E. Power has begun the assembling of apparatus for the determi- 

 nation of the phosphorescence of certain of the sulphides of Lenard and 

 Klatt at high temperatures, with special reference to the temperatures at 

 which their activity ceases. 



Dr. Frances G. Wick, at the physical laboratory of Vassar College, has 

 made spectro-photometric measurements of the fluorescence, absorption, and 

 surface color of the double cyanides of platinum. 



n. The effects of temperature upon physical properties: 



In this work it is proposed to subject substances, under conditions which 

 admit of accurate determinations of some given property, to the widest pos- 

 sible range of temperature and thus to gain more knowledge of the effect of 

 temperature upon various physical constants than has hitherto been available. 



The following investigations in this very broad field are now in progress : 



Dr. A. A. Somerville is determining the electrical conductivity of metallic 

 oxides through a range of temperatures from that at which the conductivity 

 first becomes appreciable up to 1 100° C. Preliminary reports were presented 

 to the American Physical Society on March 2 and April 27, 1912 (Physical 

 Review, xxxiv, pp. 311 and 399), and a further paper will be read at the 

 October meeting of the Society. 



Dr. F, A. Molby, assisted by Mr. A. L. Huestis, has measured indices of 

 refraction of optical glasses by the method of interference between — 190° 

 C. and 100° C. A preliminary paper, giving some of the results, was read at 

 the meeting of the American Physical Society on March 2, 1912 (Physical 



