808 



on account of the disturbing pull of all of 

 the other planets. In order, to predict the 

 position of any planet, or of the sun for 

 use in surveying and navigation, at any 

 future time, these minute changes in the 

 form and position of the orbits must be 

 rigorously calculated and allowed for. One 

 method of doing this is by obtaining any 

 variation in the form of an infinite series, 

 and then adding together as many terms of 

 this series as are thought to be necessary. 

 'The computations in the great work of 

 Le Verricr and Newcomb were performed 

 in this way. 



The German mathematician. Gauss, has 

 proved, however, that those variations of 

 the orbit of any body which increase in- 

 definitely with the time will be precisely 

 the same as the variations produced, not 

 by the pull of the other planets, but by the 

 pull of a series of elliptic rings which re- 

 spectively coincide with the oi'bits of these 

 disturbing planets. The mathematical com- 

 putation of the effect of the pull of these 

 rings on the orbit of the disturbed planet 

 leads to a definite integral instead of to an 

 infinite series. 



The present paper gives the results of 

 this computation as applied to the orbit of 

 the earth. It is part of a work on which 

 the author is engaged, which, when com- 

 pleted, will give the computation for each 

 of the four inner planets. 



On the Problem of Four Bodies: Professor 

 Edgar Odell Lovett, of Princeton. 



Radio-Activity in Solar Phenomena: Pro- 

 fessor Monroe B. Snyder, of Philadel- 

 phia. 



Evidence Relating to Latitude Variations 

 of Short Periods. From Observations at 

 the Flower Observatory During the Year 

 1904: Profesvsor C. L. Doolittle, of 

 Philadelphia. 



[N. S. Vol. XXI. Xo. 543. 



Enquiry into the Pressure and Rainfall 

 Conditiom of the Trades-Monsoon Area: 

 W. L. DalLxVs, of the Meteorological 

 Office, India. (Presented by Professor 

 Abbe.) 



Mr. W. L. Dallas, who has been promi- 

 nent for twenty years past as the first as- 

 sistant in the office of the 'Meteorological 

 Reporter to the Government of India ' com- 

 municated 'An Enquiry into the Pressure 

 and Rainfall Conditions of the Trades- 

 Monsoon Area.' This is a contribution to 

 the great problem of predicting the char- 

 acter of the approaching crop season and 

 the crop itself. In India the crop depends 

 on the rains of the southwest monsoon. 

 After they have ended the crop ripens and 

 the harvest comes before the dry season is 

 under way. Formerly we thought of the 

 southwest monsoon as a northeast trade- 

 wind from the north Indian Ocean diverted 

 toward the warm interior of Asia and the 

 slopes of the Himalayas. But the Indian 

 meteorologists, by studying the reports of 

 winds from the Indian Ocean have suc- 

 ceeded in demonstrating that the southwest 

 monsoon comes across the equator and is 

 with the southeast , trade-wind of the 

 southern Indian Ocean drawn towards In- 

 dia and Siam and China. The intensity 

 and direction depend upon the distribution 

 of barometric pressure from the Himalayas, 

 south to Cape of Good Hope on the west 

 and to Australia on the east. In fact, the 

 great area of land that we divide up into 

 three continents of Europe, Asia, Africa, 

 act as one warm area, the great dry land 

 hemisphere, to disturb the action of the 

 great water hemisphere. The dry land and 

 the aqueous hemispheres of our globe by 

 their annual warming and cooling power- 

 fully affect the general circulation of the at- 

 mosphere, transforming it into an attempt 

 at a huge whirl around the continent in 

 opposite directions in summer and winter. 



SCIENCE. 



