Chemistry and Physics. 93 



ical standpoint in a very thorough manner. The lectures are : 

 (1) The latent heat of chemical reaction and its relation to reac- 

 tion energy ; (2) and (3), Entropy and its significance in gas 

 reactions. (4) Examples of reactions which proceed without a 

 change in the number of molecules. (5) Some examples of reac- 

 tions involving a change in the number of molecules. (6) Deter- 

 mination of the specific heat of gases. (7) Determination of 

 gaseous equilibrium, with a theoretical and technical discussion. 



H. W. F. 



6. A Search for Fluctuations in the Sun's Thermal Radia- 

 tion through their Influence on Terrestrial Temperature ; by 

 Simon Newcomb. Trans. Amer. Phil. Soc., xxi, pp. 309-387. — 

 The problem of variations in solar heat radiation as affecting 

 terrestial temperatures is discussed in a thorough, impartial way 

 in this memoir. The conclusions are none the less interesting 

 because essentially negative in character, although the observa- 

 tions made by Langley and later at the Astrophysical Observatory 

 at Washington have seemed to indicate a different result. New- 

 comb shows that a careful study of the annual departures of tem- 

 perature over many regions in equatorial and middle latitudes, 

 indicate a fluctuation corresponding with the period of solar 

 spots. The maximum fluctuation, however, for tropical regions 

 is only 0-13° C, or, in other words, the amplitude of the change 

 is 0*26° C, less than one-half degree Fahrenheit. The corre- 

 sponding fluctuation of the sun's radiation is, hence, concluded 

 to be 0*2 of 1 per cent on each side of the mean. In addition, 

 there is some inconclusive evidence of changes having a period 

 of about six years, which may be plausibly attributed to changes 

 in solar radiation. Apart from these changes the evidence at 

 hand indicates that solar radiation is subject to no change pro- 

 ducing a measurable effect upon terrestrial temperature ; the 

 magnetic, electric, and radio-active emanations may be left out of 

 account, as their thermal effect is inappreciable. The ordinary 

 terrestrial phenomena of temperature, rainfall and winds are 

 thus uninfluenced by changes in the sun's radiation. That wide 

 changes of temperature may occur, as those noted in 1903, when 

 the temperature in Russia and Siberia, for example, was more 

 than 20° F. above the normal, is interesting, but it is argued that 

 these fluctuations cannot be attributed to changes in the radia- 

 tion from the sun, because they do not extend to regions (i. e. 

 the equatorial) where such changes would have their greatest 

 effect. 



II. Geology. 



1. Early Devonic History of New York and Eastern North 

 America] by John M. Clarke. N. Y. State Museum Mem., 

 IX, pp. 366, pi. 48 + . Albany, 1908. — To the important series of 

 New York State Museum publications is now added the sump- 

 tuous memoir bearing this title, the peer of a notable line of pred- 

 ecessors and decidedly the crowning achievement on the part 



