430 PROCEEDINGS OF THE ACADEMY OF [Oct.. 



forming the forest east of the divide appear to differ considerably 

 from those of the west, due doubtless to the greater precipitation of 

 moisture on the latter region. Near the limit of timber and in open 

 ground, where the effect of such conditions would not be so marked, 

 they appear to be nearly identical. 



October 16. 

 Dr. Benjamin Sharp in the Chair. 

 ^ Twenty-five persons present. 



Weather Predictions. — Mr. Harvey M. Watts remarked that a new 

 epoch is about to dawn in meteorological research, in that the United 

 States Weather Bureau expects within a month to receive daily 

 reports from the entire northern (circum-Polar) hemisphere — Europe, 

 Siberia, Alaska, and so on around from west to east — allowing the 

 meteorologists for the first time to have synoptic charts made cover- 

 ing this immense area of the inhabited globe. 



In explaining the significance of this, Mr. Watts went into a careful 

 survey of the great basic causes of weather and climate variations. 

 He called attention to the universal drift of the general circulation 

 from west to east about the Pole in the regions north of the Tropics, in 

 which general circulation are carried by the travelling cyclones and 

 anti-cyclones (centers of low and high barometric pressures), and he 

 indicated how the paths of these travelling eddies were determined by 

 the pressures and location of the sub-Tropical high pressure belts, 

 which form in the Atlantic and Pacific Oceans huge permanent anti- 

 cyclones, upon whose seasonal shifting and variations in pressure 

 depend the general variations in weather and climate. 



The speaker called attention to the fact that the variation in place 

 and pressure of these anti-cyclones (the sub-Tropical high pressure 

 belts), it was now held generally by meteorologists, were due to varia- 

 tions in the radiation from the sun. It is known that the sun is a 

 variable star, whose radiation varies from time to time as much as 

 ten per cent. 



These solar variations affect the pressure in the sub-Tropical region, 

 and the variations in the pressures in the sub-Tropical region in turn 

 affect atmospheric pressures the earth over, determining the path of 

 storms and clear weather phenomena, and also general climatic effects, 

 such as excessive rains, droughts, hot and cold summers and their 

 contraries. 



The following were ordered printed : 



