Chemistry and Physios. 69 



wick of the compressed salt was placed in it. The bolometer 

 consisted of two platinum resistances. These were formed from 

 platinum wire embedded in silver and hammered flat so as to have 

 a breadth of 0-05 ram and a thickness of 0'00036 ram . Two of these 

 resistances were placed side by side on a mica frame, one was 

 blackened and exposed to the light, the other was covered. It 

 was found that a standard candle at a distance of l m gave a throw 

 of 150 mm . A large number of carbon bands were discovered ex- 

 tending to wave length 20620. Sodium showed maxima at 8180, 

 11270, 12400 and 18360. Potassium at 7670, 10820, 11580, 12250 

 and 14610; lithium at 8070; rubidium at 7910, 9980, 13120 and 

 14760; csesiurn at 8380, a large one at 8820 and other lines at 

 9980, 13270 and 14530. 



Kayser and Range's empirical law was confirmed for the infra 

 red of lithium and sodium, but not for the other metals examined. 

 — Ann. der Physik und Chemie, No. 10, 1892. j. t. 



8. The Magnetic effect of the Sun upon the Earth. — Sir 

 William Thomson, in his address at the anniversary of the 

 Royal Society, spoke of the hypothesis that terrestrial magnetic 

 storms are due to electro-magnetic waves emanating from the 

 sun. The primary difficulty is to imagine the sun a permanent 

 magnet or an electro-magnet, sufficiently powerful to produce on 

 the earth changes of magnetic force amounting in extreme cases 

 to -Jq- or -^-g- of the earth's terrestrial magnetic force, and in ordinary 

 magnetic storms to -±^. The sun must be as a magnet at least 

 12000 times the average intensity of the earth's magnetism to 

 produce by direct action, simply as a magnet, any disturbances 

 ot terrestrial magnetism sensible to the magnetic instruments in 

 our observatories. To produce the magnetic storm of June 25, 

 1885, the sun must have worked at something like 12X10 35 ergs 

 per second, which is about 364 times the total horse power (3 - 3x 

 10" ergs per second) of the solar radiation. Thus during the 

 eight hours of a not very severe magnetic storm, the sun was 

 doing as much work in sending forth magnetic waves through 

 space as he actually does in four months of his regular light and 

 heat. To Sir William Thomson's mind, this result is conclusive 

 against the supposition that terrestrial magnetic storms are due 

 to magnetic action of the sun ; or to any kind of dynamical action 

 taking place within the sun, or in connection with hurricanes in 

 his atmosphere. We are forced to conclude that the supposed 

 connection between magnetic storms and sun spots is unreal, and 

 that the seeming agreement between the periods has been a 

 mere coincidence. — Nature, Dec. 1, 1892. j. t. 



9. Sound and Music; by the Rev. J. A. Zahm, Professor of 

 Physics in the University of Notre Dame. 452 pp. 8vo. Chicago, 

 1892 (A. C. McClurg and Co.) — This is an excellent book, present- 

 ing a subject which is always full of interest in such a way as to 

 make it doubly attractive. While accurate and scientific in its 

 statement of the laws and phenomena of Sound, it is eminently 

 popular, in the better sense of the word, in style and method, and 



