METEOROLOGY. 499 



braced under the title of " terrestrial physics." Therefore we regret, not 

 to have found Balfour Stewart's excellent article published in its proper 

 place under " terrestrial magnetism," in a succeeding volume of the 

 Encyclopaedia. 



Buchan's treatise is too short to do much more than touch upon the 

 salient points of meteorology, which he declares to be restricted to the 

 description and explanation of the atmosphere as grouped under the 

 terms u weather" and "climate." In a few words relative to the histori- 

 cal development of this study the author glances at the progress due to 

 Humboldt, Dove, Loomis, Le Verrier. Perhaps it was impossible in the 

 space at his disposal to do justice to all, but as the whole work is evi- 

 dently written for the American and English public, and is not free 

 from national prejudice, it seems strange that the great series of daily 

 weather maps 1838 to 1843, published by Espy, and the great daily map 

 of the Smithsonian Institution, 1854 to I860, should have been passed 

 by in the following very misleading sentence: "The method of practi- 

 cally conducting this large inquiry (the paths of storms) in the most 

 effective manner was devised by the genius of Le Verrier, and begun to 

 be carried out in 1858 by the daily publication of the Bulletin Interna- 

 tional, to which a weather map was added in September, 1863." This 

 paragraph seems to well illustrate the great difficulty of acquainting 

 one's self thoroughly with what is going on in divers countries, and em- 

 phasizes the importance of such indexes to the Bibliography of Meteor- 

 ology as those of Hellmann (Leipsic, 1883) and Symons (not yet pub- 

 lished). 



The wnole of this essay is divided into two capital sections — 

 i. e., "Diurnal phenomena" and "Monthly annual and irregularly re- 

 curring phenomena." Under this head the respective phenomena are 

 treated of in separate paragraphs apparently quite independent of or 

 with a very slight thread of interdependence. In the former of these 

 sections the illustrative examples are so frequently drawn from the re- 

 sults of observations made on the Challenger, or from the publications 

 that are due to Buchan, that we almost forget the numerous able co- 

 workers in this field. Among the new data and results not heretofore 

 published or but little known, the following are worthy of mention: The 

 depth below the surface of the sea to which the influence of the sun's 

 heat is felt has been shown by the observations of the Challenger to be 

 about 500 feet. The rate at which this heat is distributed in perfectly 

 clear water at different depths is a problem that has not yet been 

 worked out. During 1859 to 1863 Captain Thomas frequently observed 

 hourly the surface temperature of the sea off the northwest coast of 

 Scotland with the following results: Total mean daily oscillation of 

 temperature, 0°.3 Fahr.; minimum, 0.17, at 6 A. M.; mean, 0.0, 10 A 

 M. and 2 A. M.; maximum, +0.13, between 3 and 4 p. m. From the 

 records of the Challenger Buchan deduces the results of simultaneous 



