January 17, 1913] 



SCIENCE 



109 



Introduction to the Barer Elements. By 

 Philip E. Browning. Third edition, thor- 

 oughly revised. New York, John Wiley & 

 Sons. 1912. Pp. xii + 232. 

 Our knowledge of the rarer elements has 

 been considerably extended since 1908, when 

 the second edition of " Browning " appeared. 

 While the general scheme of the work re- 

 mains the same as in the two previous edi- 

 tions, the author has made many changes and 

 additions throughout : for instance, the chap- 

 ter on qualitative separation has been ex- 

 tended by including new analytical diagrams, 

 working directions, and notes; the chapter on 

 technical applications has been much im- 

 proved by the addition of considerable ma- 

 terial; and a table of spectroscopic lines and 

 plates illustrating typical spectra have been 

 added. The revision has been quite thor- 

 oughly done. For the first time the work has 

 been well indexed; this improvement in itself 

 greatly enhances the usefulness of the book. 



Among the omissions may be noted the fol- 

 lowing: The test for the platinum metals 

 (except osmium and ruthenium) devised by 

 Curtman and Eothberg (this is the most deli- 

 cate chemical test for platinum) ; and the 

 conduct of the platinum metals toward vari- 

 ous gases (Phillips, Am. Phil. Soc, March 17, 

 1893). 



It would be advisable in later editions to 

 give the original references to the literature 

 on technical applications, especially to the 

 patents; and to include a complete bibliog- 

 raphy of the treatises on the rarer elements, 

 if any bibliography is given. 



Charles Baskerville 



Light, Photometry and Illumination. A 

 thoroughly revised edition of " Electrical 

 Illuminating Engineering." By William 

 Edward Barrows, Jr., B.S., E.E., Professor 

 of Electrical Engineering, University of 

 Maine. New York, McGraw-Hill Book 

 Company. 1912. Pp. ix + 335. 

 Some of the science, and most of the art, of 

 illumination is still in a decidedly unsettled 

 state, and he who wishes to write a text-book 



on the subject has a narrow course to sail 

 between the Scylla of obsolescent matter and 

 the Charybdis of controversial discussion. 

 Professor Barrows apparently has more fear 

 of the first danger; at any rate, he has in 

 several parts of his new text gone perilously 

 near to the second. A considerable part of 

 the book is made up of quotations and pas- 

 sages adapted from recent papers. As a 

 resume of important articles of the last few 

 years the work is useful, and its value is aug- 

 mented by the care which has been taken to 

 give references to the original authorities. By 

 copious use of quotations the author to some 

 extent disarms criticism and shifts responsi- 

 bility to the original authors, but for purposes 

 of instruction the book would be more valuable 

 if some of the lengthy quotations were re- 

 placed by a digested presentation of the prob- 

 lems to be met and the facts supposed to be 

 established. 



The treatment of radiation which serves as 

 an introduction to the book is characterized 

 by a looseness of expression which can not fail 

 to produce hazy ideas in the mind of the stu- 

 dent. As examples may be mentioned the 

 statement that " at wave-lengths greater than 

 those of red light the energy radiated is in the 

 form of heat" (p. 1), and the naive criticism 

 of the bolometer because it " is apt to indicate 

 the heat rays rather than the luminous rays " 

 (p. 93). 



Even more serious are certain misstate- 

 ments of fact, e. g., " since the radiation varies 

 as the fourth power of the temperature, it is 

 evident that the greatest efiiciency of radiation 

 will be obtained at the highest temperatures," 

 and " it follows from the above that the effi- 

 ciency of the source as an illuminant will vary 

 greatly with the temperature" (p. 4). These 

 statements precede any mention of the real 

 cause of the increase in efficiency, that is, the 

 shifting of the radiation toward shorter wave- 

 lengths with rise of temperature. 



The discussion of the Luminous Equivalent 

 of Radiation in Chapter III. is anything but 

 clear. Its vagueness is due in part to the 

 promiscuous use of terms without definitions. 



