December 13, 1895.] 



SCIENCE. 



817 



of refraction, and the values computed ft-om 

 Fresnel's theory of vitreous reflection and re- 

 fraction are in close agreement with the ob- 

 served amounts of polarization. 



On Ternary Mixtures III. By W. D. Bancroft. 



The present article, which completes a series 

 of three papers on this subject, deals with liquid 

 mixtures in which two components are partially 

 miscible, while the third is miscible with these 

 in all proportions. The ' Mass Law ' is found 

 to hold in this case as well as in the case dis- 

 cussed in the previous articles. In support of 

 his Conclusions the author presents not only his 

 own observations, but also the numerous results 

 previously obtained by other observers. It is 

 found that in general there are four sets of 

 equilibria. Dr. Bancroft discusses also the ques- 

 tion of the distinction between the solvent and 

 a dissolvent substance, and is of the opinion that 

 there is a fundamental difference between the 

 two. 

 On the Changes in Length Produced in Iron Wire 



by Magnetization. By L. T. Moore. 



After a brief review of the work previously 

 done on this subject the author describes ex- 

 periments to determine the elongation of soft 

 iron wire as a function of the magnetization. 

 The apparatus used had a multiplying power of 

 37,000 and permitted the use of a field as high 

 as 260. Precautions were taken to obtain uni- 

 form magnetization, and the latter was directly 

 measured. It was therefore possible to plot 

 the elongation in terms of the magnetiza- 

 tion, rather than in terms of the field, as has 

 usually been done heretofore. After correcting 

 for the contraction due to the magnetic force 

 between adjacent parts of the iron, the maximum 

 elongation was found to occur at an intensity 

 of magnetization of about 1,200. Beyond this 

 point the elongation diminished. The effect of 

 hardening was investigated, and measurements 

 were also made when the wire was subjected to 

 tension. 



The number contains minor articles on the 

 Limits of Pitch for the Human Voice, by W. 

 Le Conte Stevens ; and the New Physics Lab- 

 oratory at Lille, by E. L. Nichols. 



Book reviews: Hertz, Electric Waves; Glaze- 

 brook, Mechanics. 



AMERICAN METEOROLOGICAL JOURNAL 

 DECEMBER. 



Meteorology as a University Course. By Robert 



Dec. Ward. 



The science of meteorology has been largely 

 built up by Americans, as the names of Frank- 

 lin, Eedfleld, Espy, Maury, Coffin, Henry, 

 Ferrel and Loomis — known all over the world 

 — show, and yet the study of the subject in this 

 country is by no means as general or as syste- 

 matic as it should be. The author pleads for 

 more instruction in general meteorology, and 

 advises the consideratidn of the various subjects 

 in the following order : Evolution , composition 

 and offices of the atmosphere and its relations 

 to plants and animals; relations of earth and 

 sun ; the variations of the seasons and the dis- 

 tribution of temperature over the earth's sur- 

 face for the year, January and July, together 

 with a study of isanomalous and of equal an- 

 nual range charts; the distribution of pressure 

 for the year, January and July, and the result-* 

 ing winds; classification of the winds ; moisture 

 of the atmosphere and precipitation ; storms, 

 including cyclones, thunderstorms and torna- 

 does ; distribution of rainfall over the world, by 

 seasons and for the year; weather; climate, in- 

 cluding sanitary climatology, secular changes 

 in climate and the relation of climate to history. 



Abundant and attractive illustratioHS may 

 easily be secured for such a course, as, e. g., the 

 daily weather maps, barograph and thermograph 

 curves ; temperature, pressure, wind, cloud and 

 rainfall charts; photographs of clouds, light- 

 ning, snow crystals, damage by tornadoes, etc. 



A large field of investigation is open to those 

 who have completed a course in general meteor- 

 ology, and yet who have not advanced far into 

 physics or mathematics. Among the lines of 

 work suggested are the following : The careful 

 study of the climates of the different States, 

 the effects of their topography on their rainfall, 

 their winds and the courses of their local 

 storms; the local effects of forests and of culti- 

 vation on rainfall ; the distribution of rainfiill by 

 seasons, months anl districts, and its bearing 

 upon the times of planting and harvesting; the 

 changes in the depth of the ground- water level, 

 and its variations with the weather and with 

 the season. 



