On the General System of Winds on the Earth. 497 



current in the coil, in one direction when the beam was sent 

 along the specimen, and in the opposite direction when the 

 beam was interrupted. If the effect were too small to be 

 detected by a galvanometer in this way, perhaps it might be 

 found by alternately interrupting and restoring the beam by 

 a rapidly rotating perforated screen, and listening for sound 

 in a telephone included in the circuit of the coil. 



LVII. On the General System, of Winds on the Earth. 

 By Werner von Siemens.* 



IN" the May number of the Meteorologische Zeitschrift there 

 is a paper by Dr. Sprung, entitled ei On the Theories of 

 the General System of Winds on the Earth," in which the 

 calculations of the direction and strength of general currents 

 of air set forth in~my communication to the Academy, of the 

 4th March, 1886, " On the Conservation of Energy in the 

 Earth's Atmosphere " f , are critically compared with Ferrel's 

 old theory. This paper induces me to make the following 

 observations which, however, are not directed against Dr. 

 Sprung's objections to the strict validity of the results of my 

 calculations, which objections are to a certain extent quite 

 just, but against the supposition that I have attempted, like 

 Ferrel, " to found on theoretical calculations a theory of the 

 general system of winds on the earth." Apart from not con- 

 sidering myself a sufficient adept in mathematics, I may say 

 that I consider this method altogether inappropriate. So 

 very complicated a problem as that of the general system of 

 winds cannot possibly be constructed a priori on the basis of 

 mathematical calculations, as up to now no simple basis has 

 been found underlying all the phenomena. In my treatment 

 "Of the Conservation of Energy in the Earth's Atmosphere," 

 I first sought to determine the forces which produce, main- 

 tain, and retard the motion of the air, and then to find by 

 calculation the direction and magnitude of the general motion 

 of the air induced by their combination. It is therefore not 

 correct " that I sought like Ferrel to demonstrate by means 

 of calculation an original state of atmospheric motion in order 

 afterwards to base my further speculations thereon." Nor is 

 it correct that I have taken no account in my calculations of 

 the retardation of the motion of the air through friction, for 



* Translated from the Sitzungsberichte der Koniglich Preussischen 

 Akademie der Wissenschaften zu Berlin, 1890, xxx., by E. F. Bamber. 

 Communicated by the Author. 



t Phil. Mag. vol. xxi. 1886, p. 453. 



