120 



THE POPULAR SCIENCE MONTHLY. 



Report of the Commissioner of Educa- 

 tion FOR 1878. Washington: Govern- 

 ment Printing-office. 1880. Pp. 730. 



The office of the Commissioner of Edu- 

 cation is a peculiar one. It has no author- 

 ity, but depends wholly upon voluntary as- 

 sistance for the collection of the informa- 

 tion which it undertakes to digest and dif- 

 fuse, and its recommendations, if it makes 

 any, can pass only for what they are intrinsi- 

 cally worth. Its function, as the Commis- 

 sioner well remarks, is that of '"a national 

 clearing-house ' of educational information, 

 where what has been done is carefully record- 

 ed, and that which indicates the good or bad 

 may be selected." That its work is more 

 appreciated every year is shown by the 

 steadily increasing number of its correspond- 

 ents at home, who numbered 7,135 in 1878, 

 and the extension of its connections abroad. 

 The present volume contains full informa- 

 tion, with all the details, on the condition of 

 public and private education in the United 

 States, arranged by States, and according to 

 the grade and character of the institutions, 

 and one of the most satisfactory accounts of 

 the condition of education in foreign coun- 

 tries that the Commissioner has yet been 

 able to present. 



Photometric Researches. By William H. 

 Pickering. Extracted from the Pro- 

 ceedings of the American Academy of 

 Arts and Sciences. Cambridge, Massa- 

 chusetts: University Press. 1881. 



Vert little is known with accuracy of 

 any terrestrial high temperature, while esti- 

 mations of that of the sun vary between the 

 extreme limits of several million and two 

 thousand degrees. In the researches to 

 which this paper is devoted. Professor Pick- 

 ering has endeavored to determine some of 

 these temperatures by means of the amount 

 of violet rays given off, these being the rays 

 most abundant at the highest temperature. 

 The exact relation between these factors is 

 unknown, but, by assuming one which his 

 experiments led him to regard as probable, 

 Professor Pickering has been able to make 

 out a table which does not differ widely 

 from the most reliable determinations here- 

 tofore made. The lights of a candle, gas- 

 flame, lime, magnesium, the electric arc, 

 moonlight, and sunlight were each examined 

 by means of a spectroscope and photome- 



ter, and the relative brilliancy of the red, yel- 

 low, green, and violet rays determined. The 

 standard used was an Argand gas-flame with 

 a small screen interposed, so that the light 

 yielded was just '67 candle-power, and a 

 candle was found to be wholly unsatisfac- 

 tory for the purpose. The relative inten- 

 sities of these portions of the spectrum were 

 in each of the lights as follows, that of the 

 yellow rays being taken at 100 : Candle, 73, 

 100, 104, 134; gas, 74, 100, 103, 125; lime, 

 59, 100, 113, 285 ; magnesium, 50, 100, 223, 

 1,129; electric light, 61, 100, 121, 735; 

 moonlight, 87, 100, 155, 363 ; sunlight, 45, 

 100, 250, 2,971. The great preponderance 

 of the violet rays in burning magnesium 

 over those of any other artificial light clearly 

 indicates a higher temperature, while by the 

 same test that of the sun is much greater. 

 The temperatures for all the lights measured 

 are : Candle and gas, 1,200 C. ; lime, 2,000 

 C, about that of melted platinum ; electric 

 arc, 3,500 C. ; magnesium, 4,900 C. ; sun, 

 22,000 C. This method of obtaining tem- 

 peratures gives promise of being of great 

 value, for, as pointed out by Professor Pick- 

 ering, if the relation between increase of 

 temperature and increase of violet rays were 

 accurately determined, we could very readily 

 determine the temperature of the heavenly 

 bodies. 



Studies op the Food of Birds, Insects, 

 AND Fishes, made at the Illinois State 

 Laboratory of Natural History. Nor- 

 mal, 111. Paper. Pp. 160. 



The State Legislature of Illinois recently 

 authorized an investigation of the food of 

 the birds of the State, with especial refer- 

 ence to agriculture and horticulture, and a 

 similar investigation of the food of fishes, 

 with especial reference to fish-culture. The 

 papers in this collection are the first results 

 of the work. As the investigation proceed- 

 ed it was found that, to be full, it must 

 include a consideration of parts of the gen- 

 eral subject of the reactions between groups 

 of organisms and their surroundings, organic 

 and inorganic. With this view the special 

 papers are preceded by a more general one 

 on *' Some Interactions of Organisms." Pa- 

 pers are also given on " Insectivorous Cole- 

 optera," and on " The Food of Predaceous 

 Beetles." 



