PHYSICS. 411 



At Cleveland, in addition to the seiche with a period of 13.1 hours 

 which has already been noted as prevailing there, a seiche with a much 

 shorter period, 2.6 hours, was also found as a rule. The evidence is 

 reasonably clear that this short-period seiche at Cleveland is a deep- 

 water oscillation, crosswise the lake, between the 10-fathom curve near 

 Cleveland and the 10-fathom curve near the opposite part of the Cana- 

 dian shore. 



Howe, Henry M., Bedford Hills, New York. Research Associate in Metal- 

 lurgy. (For previous reports see Year Books Nos. 6-18.) 



Early in the present fiscal year I brought back to Bedford Hills, 

 New York, my laboratory, which in 1918 had been moved to the U. S. 

 Bureau of Standards, Washington, to facilitate the war work which I 

 was then doing. 



During most of this year I have been engaged in determining the 

 limits of the conditions of thermal treatment which result in bringing 

 steel into the sorbitic state, the most advantageous state for most 

 engineering purposes. 



Much new apparatus has had to be assembled for this purpose, and 

 some of it has had to be designed. The conditions resulting from the 

 war have retarded this work. The results are not yet ready for pub- 

 lication. 



With Mr. F. B. Foley, and at the request of Professor C. E. Mumoe, 

 chairman of the committee on explosives investigations, National 

 Research Council, I ascertained that the abundance of mechanical 

 twins, called "Neumann bands," set up by explosion or impact in low- 

 carbon steel, increases with the velocity of impact till this passes 2,296 

 meters per second, and is greater with 3,190 than with 2,296 meters. 

 With further increase in velocity no further increase in abundance 

 could be detected. 



Nichols, E. L., Cornell University, Ithaca, New York. Report on studies 

 in luminescence. (For previous reports by Dr. Nichols, see Year Books 

 Nos. 4-18.) 



Fluorescence at High Temperatures. 



Since the recent completion of our monograph on the uranyl salts, ^ 

 attention has been directed chiefly to luminescence at high tempera- 

 tures. This is an entirely new field, it having hitherto been assumed 

 that, with the discharge of thermo-luminescence at temperatures some- 

 what below the red heat, all luminescent activities vanish, very much as 

 magnetization of iron ceases at the temperature of transformation. 



We find, on the contrary, that many oxides, notably CaO, MgO, ZnO, 

 Zr02, Si02, and AI2O3 are fluorescent throughout a much higher range 

 of temperatures — roughly to an upper limit frequently lying between 



^Fluorescence of the Uranyl Salts: E. L. Nichols and H. L. Howes, in collaboration with Ernest 

 Merritt, D. T. Wilber, and Frances G. Wick, Carnegie Inst. Wash. Pub. No. 298, 1919. 



