Chemistry and Physics. 173 



it should be observed that a large part of the inorganic analysis 

 of thirty years ago is applicable at the present time, and that 

 this classical work of Fresenius must still be considered the stand- 

 ard reference book on the subject. h. l. w. 



5. The Analytical Chemistry of Uranium; by Harry Brear- 

 ley. 8vo, pp. 45. London, 1903 (Longmans, Green & Co.). — 

 This little book deals chiefly with the author's experience in 

 determining uranium, in separating it from the associated ele- 

 ments, and in descriptions of analyses of uranium minerals. In 

 view of the present importance of uranium ores as sources of 

 radium, it seems remarkable that this interesting metal is not 

 mentioned in the book under consideration in the list of elements 

 occurring in pitchblende. It is still more remarkable that the 

 author apparently is not familiar with the discovery of helium, 

 for he mentions nitrogen as a constituent of pitchblende and 

 refers only to Hillebrand's work on this subject. h. l. w. 



6. Chemical Calculations ; by H. L. Wells. 8vo, pp. 58. 

 New York, 1903 (Henry Holt & Co.). — The first thing noticed on 

 opening this book is the excellent arrangement of the logarithm 

 tables, which are provided with a thumb-index and are exceed- 

 ingly convenient for such calculations as a chemist usually has to 

 make. There is a table of gravimetric factors for calculating 

 analytical results which is very complete, and a convenient set of 

 tables to be used for gases. Also, a table for calculating indirect 

 analyses, and another to be used in calculating fluxes to form 

 slags. The second part of the book explains briefly, with examples, 

 how the tables are used. n. w. r. 



7. Solar Radiation and the Pressure of Light. — This subject 

 is discussed in an important paper by Professor Poynting of the 

 University of Birmingham. The author takes the fourth power 

 law, R = 86% where R is the energy radiated per sec. per cm. by 

 a full radiator at temperature 6° A (A stands for the absolute 

 scale) and 8 is the constant of radiation. According to Kurl- 

 baum 



<r = 5-32X10- 5 erg. 



Taking the various values given by different observers of the 

 solar constant, Poynting calculates the effective temperature of 

 the sun, and places it between 6000° A and 7000 A — more exactly 

 at 6200° A. The effective temperature of space is then 10° A. 

 If a body, therefore, is raised to a small multiple of 10° — say 60° 

 — the fourth power law of radiation implies that it is giving out 

 and, therefore, receiving from the sun more than a thousand 

 times as much energy as it is receiving from the sky. The sky 

 radiation can, therefore, be left out of account, when we are 

 dealing with approximate results, and bodies in the solar system 

 may be regarded as being situated in a zero enclosure except so 

 far as they are receiving radiation from the sun. 



On the supposition that the moon does not conduct inward, its 

 upper limiting temperature is found to be 371° A, just below the 

 temperature of boiling water. Langley estimated the tempera- 



