CHEMISTRY. 331 



4. The Chemistry of Substances at High Temperatures. 



This line of research and the one described under 5, which are the main 

 ones to be undertaken with the aid of the increased resources now available, 

 have already been initiated. The study of the chemical compounds that are 

 formed in increasing proportion under the influence of very high tempera- 

 tures or of powerful radiations is not only important from the standpoints of 

 pure and applied chemistry, but of great interest to astrophysicists, because 

 of the aid it may be expected to afford in interpreting solar and stellar phe- 

 nomena. The cordial assistance which members of the staff of the Mount 

 Wilson Observatory have afforded assures successful cooperation in the 

 prosecution of these investigations. 



The first work that has been undertaken in the high-temperature field has 

 for its purpose the experimental confirmation of the theory of Saha in regard 

 to the thermal ionization of elements by reactions such as Na = Na + + E - , 

 where E~ represents the negative electron. This theory has received great 

 attention from astronomers because of the explanation it affords of many 

 spectral phenomena. A study of the literature showed that there exist 

 investigations on the electrical conductivity of flames which can be utilized 

 in testing the Saha theory; and in cooperation with Professor H. A. Wilson, 

 of the Rice Institute, who carried out the most complete of these investi- 

 gations, papers have been prepared and presented in outline before the 

 National Academy of Sciences and published in detail in the Astrophysical 

 Journal and Journal of the American Chemical Society, in which it is shown 

 that the experiments on the conductivity of gas flames into which salt solu- 

 tions have been sprayed afford, within the rather large limits of error of these 

 experiments, a striking confirmation of Saha's conclusions. 



In order to obtain conductivity measurements of salt vapors under more 

 definite conditions of temperature and pressure than is possible in flames, an 

 investigation has been undertaken at the Mount Wilson Observatory by Dr. 

 A. S. King of that institution, in cooperation with Professor A. A. Noyes of 

 this laboratory. The apparatus, consisting of an electric furnace in which is 

 heated a graphite tube provided with a concentric electrode, through which 

 nitrogen gas charged with a known proportion of salt vapor is passed, has 

 been constructed and used for preliminary measurements. 



Another distinct but related line of research, for which preparations are 

 being made, is the determination of vapor-densities of substances at very high 

 temperatures. For this purpose arrangements have been made with the 

 Research Laboratory of the General Electric Company for the construction 

 of a molybdenum bulb of the Viktor-Meyer form, which can be heated to 

 about 2400° C. This has been made possible by the friendly assistance of 

 the director, Dr. W. R. Whitney, and of the Assistant Director, Dr. W. D. 

 Coolidge, of that Laboratory. We are also greatly indebted to Dr. R. C. 

 Tolman, former director of the Fixed Nitrogen Research Laboratory, and to 

 Dr. Karrer of that Laboratory, for the aid they afforded in working out the 

 best method of heating the molybdenum bulb in an induction furnace. 



5. Effect of Radiations and Electric Discharges on the Rate and Equilibrium of 



Chemical Reactions. 



During the past year an investigation has been carried out by Dr. D. F. 

 Smith, in this laboratory, on the rate of decomposition at 280° to 350° of 



