188 Scientific Intelligence. 



10. Investigations in Radiation. — The recently issued number 

 of the Bulletin of the Bureau of Standards (vol. v, No. 2) con- 

 tains two articles on radiation to which attention should be called 

 here. The first, by W. W. Coblentz, gives the result of experi- 

 ments on the selective radiation from various solids. This is 

 practically an examination of the emission spectra of electrical 

 insulators, or transparent media, as they are called ; a line in 

 which, thus far, almost no work has been done. The substances 

 used were either in the form of solid rods, made in an oxy-hydro- 

 gen flame, or of thick layers of the substance spread as a paste 

 upon the heater of a Nernst lamp. The rods were heated by an 

 electric current from the secondary of a 2000-volt 300-watt trans- 

 former. The substances examined included a series of oxides, 

 as those of zirconium, cerium, thorium, uranium, etc. ; also the 

 minerals oligoclase, albite, orthoclase, beryl, rutile, apatite, cal- 

 cite. All of these showed prominent emission bands at certain 

 points; thus the oxides have a characteristic band at 2*8 to 3/a 

 and a second group of bands at 4*5 to o/x, which may be due to 

 the common element oxygen. The silicates have also a sharp 

 emission band at 2*9/>t characteristic of Si0 2 . In the case of oligo- 

 clase it is noted that the general emission, in distinction from the 

 bands of selective emission, is less intense than in the other 

 silicates studied. Further, the isochromatics of oligoclase are 

 peculiar in that for it the emissivity is proportional to the energy 

 consumed. 



A second article, by P. G. Nutting, is an important discus- 

 sion of the luminous equivalent of radiation, from the standpoint 

 of both objective and subjective light and with especial reference 

 to the establishment of a more precise relation between light and 

 its radiation, by which it can be alone measured. 



II. Geology. 



1. United States Geological Survey, Twenty-ninth Annual 

 Report, 1907-1908, of the Director, George Otis Smith. Pp. 

 v, 99, with two plates. — This report contains a statement of the 

 work done by the various divisions of the Survey during the fis- 

 cal year ending June 30, 1908. The freedom from political 

 influence, the efficiency, and the high scientific esprit de corps 

 which have marked the Geological Survey since its origin have 

 caused it to be intrusted with various added branches of work 

 which after a period of development have been organized as sepa- 

 rate bureaus. This is the history of the Forest Service and the 

 Reclamation Service. The technologic branch has had a more 

 recent inception and the question is now under consideration by 

 Congress as to the advisability of its development into a separate 

 bureau of mining technology. Such a bureau would supplement, 

 along purely technologic lines, the geologic work of the Survey, 

 and the two bureaus could cooperate in investigations carried on 



