232 PROGRESS OF METEOROLOGY IN 1889. 



land and water over the earth's surface. In previous researches on the 

 distribution of heat, the mean vaUies have been determined and based 

 upon empirical observations; but Dr. Zenker has calculated the distribu- 

 tion of heat over the surface of the sea with the help of Hann's isothermal 

 charts, starting with the temperature of a point on its surface which 

 was quite uninfluenced by the neighboring continents, and was conse- 

 quently equally unaffected by any warm or cold current. Using this 

 factor, and the formuhie deduced in the theoretical part of his paper, 

 he has calculated the distribution of heat from the pole to the equator 

 for each successive i^arallel, and compared it with the distribution of 

 solar radiation. As a basis for the distribution of heat over the surface 

 of the land, it was first necessary to determine the condition imder which 

 the influence of tlie neighboring sea is either nothing or minimal in 

 amount. The starting point for this was the fact that the temperatures 

 on the continents exhibit very great variations, and from these was 

 determined for each area, as a percentage, the relative influences of the 

 sea and continent upon its temperature. The region where the influ- 

 ence of the sea was proved to he nil (or where the "continentality" 

 was 100 i^er cent.) was in the neighborhood of the east coast of Asia, 

 whereas all other points were found to be affected by the neighboring 

 sea to a greater extent. The observed temperature on the land was 

 therefore only partly dependent upon the position of the place on any 

 given parallel, other influences making themselves more or less felt. 

 Hence it was possible to calculate for each i^arallel the real and " acces- 

 sory" temperature. The amount of heat radiated from the sun was 

 compared with these temperatures, and was found to be about the same 

 for each 10° C. of difference in temperature ; from 0° to 10° C. however, 

 quite considerable difierences in radiation were necessary. In conclu- 

 sion. Dr. Zenker compared the temperatures which really exist on the 

 earth's surface with those which he had deduced, and found that in re- 

 ality the climate on the sea in the southern hemisphere is colder than it 

 should be according to calculations — a result which must be attributed 

 to ocean currents of cold water. The continental climate in the north 

 ern hemisphere is slightly too warm, in consequence of the effect of the 

 Gulf Stream. {Nature, xxxviii, p. 48.) 



Terrestrial temperature. — Mr. Arthur Searle in a paper entitled 

 "Atmospheric economy of solar radiation," discusses the manner in 

 which the assumed protective action of the atmosphere maintains tef- 

 restial temperatures. Since the supposed eifect of selective absorption 

 whereby the atmosphere was supposed to be more diathermauous to solar 

 than to terrestrial radiation, has been largely disproved by Laugley's 

 exi)eriments, the author points out that heat transferred from the earth 

 to the air by conduction and convection is not radiated into space with 

 the same facility as it would be if radiated directly from the earth's sur- 

 face. The iucrease of energy thus accumulated in the atmosphere is 

 checked by the development of atmospheric movements. Warm air is 



