288 British Association for the Advancement of Science, 



the top of a shot-tower 162 feet high ; another was near the 

 ground within the enclosure about the tower ; and the interme- 

 diate one was the roof of the University. His attention was 

 however ultimately fixed upon the fact that the eflFect of eddy 

 winds upon the observed phenomena, was by no means a secon- 

 dary one in amount, and that no law could be deduced, until this 

 disturbing action was prevented. Prof. B. proceeded to make 

 experiments on the effects upon the rain-gauges of the currents 

 of air deflected by the tower, placing gauges at each angle. The 

 results are given in a table, from which it appears that — 1. The 

 quantities of rain collected at the different angles of the tower 

 were very different. In one extreme case the quantity collected 

 at the S. E. angle was 2| times that at the N. W. angle. 2. In 

 general, the gauges to leeward received more rain than those to 

 windward. Prof Stevelly considered the fact that less rain was 

 caught in elevated gauges than in those near the earth, to be due 

 to the greater perpendicularity with which the rain falls near the 

 ground, and not to a continued enlargement of the drops, during 

 their descent, by new accessions of condensed moisture. 



Dr. Daubeny read a paper on the Clitnate of North America. 

 He began by observing, that although the general fact was ad- 

 mitted that the E. portions of the New World had a lower tem- 

 perature than the W. portions of the Old, yet much remains to 

 be done before the relative climate of these two portions of the 

 globe can be regarded as in any degree determined. Most of the . 

 North American observations were not sufficiently accurate. In 

 Canada, Mr. McCord's observations at Montreal were the best j 

 and in the U. S., those made in N. Y., and published by the Re- 

 gents of the University of that State. These results are how- 

 ever defective, in not giving the intensity of solar radiation, 

 which probably affects the distribution of plants and animals in 

 a manner quite distinct from its accompanying temperature. 

 Hence, though many plants which grow in this country are 

 killed by the winters of comparatively southern latitudes in 

 America ; yet others, which require the warmth of a wall or of 

 a southern aspect here, are found in comparatively high latitudes 

 in the New World. Sir D. Brewster called attention to the im- 

 portant fact, clearly established by the observations recorded in 

 the neighborhood of New York, and those of Hansteen and Er- 

 man in Siberia, that two points of maximum cold existed in these 



