244 PEOGRESS OF METEOROLOGY IN 1889. 



General circulation of the atmosphere, — M. Moller contributes an arti- 

 cle to Aus dem Archiv dcr Deiitschen Beewarte on the circulation of tbe 

 atmosphere between the equator and the poles. The results arrived at 

 differ from those of Professor Ferrel, especially with regard to the force 

 of westerly winds in latitude 38" in the lower and upper strata. 



M. Weyher has instituted a most interesting series of experiments 

 designed to illustrate the cyclonic phenomena of the atmosphere, espe- 

 cially tornadoes, water-spouts, and dust whirls, and has found that his 

 results agree in every point with those deduced from the mathematical 

 theory of their movement. In one of his first experiments M. Weyher 

 shows the analogy between water eddies and air whirls. In the water 

 eddy the source of action must be at some distance below the surface, 

 while in the air whirls the source of action must be located in the upi^er 

 I)art of the air column, and the motion is communicated downwards. 

 The most interesting of his experiments are those in which he artifi- 

 cially produces the phenomena of the water-spout. Bymeansof a rotating 

 tourniquet placed over cold water, an aerial eddy is caused which draws 

 up the water, in the form of a spout composed of drops, to a considerable 

 height; but when the water is heated, a clearly defined condensed vapor- 

 spout makes its appearance. With from fifteen hundred to two thousand 

 rotations per minute the vapor from the heated water is found to cou 

 dense itself into a visible sheet enveloping a clearly defined and rarefied- 

 central nucleus, conical, and tapering downwards. Besides this vapor- 

 spout, water drops are carried up as in natural water spouts until they 

 are thrown out beyond the influence of the upward current; the press- 

 ure and temperature conditions in different parts of the area are also 

 investigated by means of a manometer. It was found that the rarefac- 

 tion at the center of the tourniquet is transmitted almost unaltered in 

 intensity to the center of the whirl on the surface, while the thermome- 

 ter at the same time at first shows a fall and then a rise of temperature 

 the latter evidently due to the friction of the rapidly moving air against 

 the surface. 



The analogous phenomena of a cyclone are very fairly imitated by an 

 apparatus consisting of a large tonrni(|uet placed over a table covered 

 with a number of pins mounted with movable threads of wool; the 

 tourniquet is mounted so as to be capable of translation as well as rota- 

 tion, and changes of pressure are registered by a numometer which 

 connects with a hole in the surface of the table by means of a rubber 

 tube. On rotating the tourni(pu>t and giving it a forward motion, the 

 directions and positions of the threads show both the horizontal and 

 vertical components of the winds thus produced, including the region 

 of calm in the center as well as the outward and downward motion at 

 the anti-cyclonic border. The variations of pressure, when pointed 

 out, show a curve similar to that in a syjn metrical cyclone. 



flail is explained as being caused by vapor drawn up into the center 

 of a cyclonic system, and is essentially similar to the explanation given 

 by Ferrel and Moller. These ex[)eriments do not of course fulfill all 



