22 E. Loomia — Contributions to Meteorology. 



storm, while the westerly winds on the rear were still 



and on this day the rain-fall v 



apo'.is 34b' inches; St. Louis 2'tiO: Cincinnati 2-47; Louisville 



2-30; Toledo 1-93; Nashville 1-90; Detroit 1-68; Cairo 1-22; 



Davenport 111, and Chicago 1-02. 



Dec. 4th, at the time of the morning observation, the winds 

 were similar to what they had been on the preceding day, and 

 considerable rain-fall was reported; but after the morning ob- 

 servation the rain everywhere ceased almost entirely and the 

 south winds on the front of the low center had mostly disap- 

 peared, and were succeeded by winds from the west or south- 

 west. At 435 P. M. only one case of high wind from the south 

 was reported, viz: at Toledo, and there is reason for believing 

 that this observation was an error, or that it represented only a 

 temporary veering of the wind, for at no other place within 

 e of 500 miles was the wind reported from the south. 

 It will be observed that after Dec. 1st, on the front side of the 

 storm there was no strong wind from any easterly quarter ; 

 and the strong winds from the south ceased at about the same 

 time as the rain ceased; while the westerly winds continued to 

 blow with unabated force for 24 hours longer. After midnight 

 of Dec. 3d the westerly winds encroached rapidly upon the 

 south winds; and by the afternoon of the 4th had almost 

 entirely supplanted them. This example seems to show that 

 the diminution of pressure in front of a great storm is mused 

 by a warm wind containing a large amount of vapor, and that 

 tse of pressure in the rear of the storm is caused by a 

 colder wind containing a less amount of vapor; and that when 

 the former winds are the strongest, there is an abundant rain- 

 fall, and the pressure at the center of the low area diminishes ; 

 but when the latter winds are the strongest, the rain-fall declines 

 and the pressure at the center of the low area increases. 



In order to prosecute these enquiries under different geo- 

 3, I have prepared a catalogue showing the 

 principal rain-falls in Europe for a series of years, but am 

 compelled to defer its publication until my next article. 



Since the publication of my paper on the mean annual rain- 

 k'U h>r dill't'ivnt countries of' the globe, I have received a con- 

 siderable number of letters communicating rain-fall observa- 

 tions. As, however, I am hoping to obtain further observations, 

 I shall defer a little longer the publication of the materials 

 ln\id ivcer i M< nui ij an\ i.-t >n> ._!' has informa- 

 tion which would be useful in preparing a revised edition of 

 my rain-chart, he is n- , furnish me a copy 



of the observations. 



