SERIES C. VELOCITY TABLES. 639 



Column I contains the name of the place of observation, to which is prefixed 

 the zone and serial number, by reference to which on the preceding pao-es the 

 reader can find the average velocity of the wind from each point of the compass 

 for each of the seasons. See, for example. Red Eiver Settlement ; near the foot 

 of page 148 we find, " Mean velocity in miles per hour. Spring, North 5.32, N. E. 

 2.71," etc. The places. are also grouped — not as by the author, in strict sequence 

 of latitude and longitude— but to conform as nearly as practicable to the divisions 

 of the United States made in the " Discussion and Analysis of Winds." 



Column II was computed as in all the tables of Series B, by having regard only 

 to. the number of observations, without any reference to velocity. 



angle of 11° 32'; and southerly in one at an angle of 8° 38', making the average of the whole 

 northerly by 15° 13' ; while it increases the magnitude of the resultant in 5 of the districts by an 

 average of 50 per cent., and diminishes it in 5 by an average of 15 per cent., making for the whole 

 an average increase of 18 per cent. 



" In 44 districts between the 40th and 45th parallels (exclusive of Great Salt Lake City where the 

 results are too anomalous to be incorporated with the others), the resultant is thrown northerly in 

 36 at an average angle of 15° 49', and southei'ly in 8 at an average angle of 4" 31', making the 

 average for the whole northerly by 12° 8'. The influence on the direction seems generally to be 

 much greater in the western thaij in the eastern States of this belt, and this accounts for my failure 

 to detect it when I prepared my former publication. The magnitude of the resultant is increased in 

 36 by an average of 29 per cent., and diminished in 8 by an average of 14 per cent., making for the 

 whole an average increase of 21 per cent. In 20 districts between the parallels of 36i° and 40° the 

 resultant is thrown northerly in 17 at an average angle of 16° 36', and southerly in 3 at an average 

 angle of 4° 11', making the average for the whole northerly by 13° 29', while its magnitude is 

 increased in 19 districts by an average of 43 per cent., and diminished in but one, and that only by 

 11 per cent., making for the whole an average increase of 36 per cent. 



" The near coincidence of the results in these three belts authorizes us to combine them, and we 

 thus find that the mean influence from the parallel of 50° down to that of 36^° is to render the 

 resultant more northerly by about 13°, and to increase its magnitude about 25 per cent. This dif- 

 ference is not great, but may alfect the general principle. 



" Through the States of Tennessee and North Carolina, from latitude 35° to 36i°, the resultant is 

 thrown northerly in 4 districts at an average angle of 18° 5', and southerly in one at an angle of 

 33° 57', the average for the whole being 7° 41' northerly. Most of the observations in the latter 

 district were taken at Knoxville, Tenn., where there may be some local cause that renders the south 

 and southwest winds so much stronger than those from the north and northwest. In each of the 5 

 districts the magnitude of the resultant is increased, the average increase for the whole being 40 

 per cent. Notice the accumulating increase of the magnitude of the resultants as we pass southerly 

 through the 4 belts above described, viz., 18, 21, 36 and 40. 



"The results in the next belt extending from latitude 30° to 35° seem perfectly chaotic. In 7 out 

 of 16 districts the resultants are thrown northerly at angles ranging from 1° to 126°, and in 9 

 southerly with nearly as wide a range, the average for the whole being 3° 23' northerly. The mag- 

 nitude of the resultants is increased in 7 districts and diminished in 9, the average being an increase 

 of 2^ per cent. It is within this belt that the system of westerly winds breaks up and is replaced, 

 as we go south, by the trade wind system, and the slight degree of prevalence of the wind in any 

 direction allows it to be controlled very much by local influences. 



"Still further south out of 6 districts represented, at 5 the resultant is thrown northerly at an 

 average angle of 17° 48'. The remaining district is represented by the City of Mexico, where the 

 general results are in some degree anomalous, and make a longer period of observation desirable 

 In 5 of these districts the magnitude of the resultant is increased by an average of 25 per cent., 

 while in one it is diminished by 8 per cent. The average increase for the whole being 19i per cent." 



