FIFTH ANNUAL MEETING. 63 



year was 168, counting those days clear on which the average cloud- 

 iness did not exceed one-third of the sky; the number of half clear 

 days was 93, including under this designation, those days on which 

 between one-third and two-thirds of the sky was covered with clouds; 

 the number of cloudy days was 105, when two-thirds or more was 

 covered. There were thirty-four entirely clear days, without a trace 

 of a cloud; there were only twenty-three entirely cloudy days, with- 

 out a trace of sky. May was the cloudiest month, when the average 

 cloudiness was 55.27 per cent.; October was the clearest month — 

 the clearest in five years — only 21.40 per cent, of the sky being 

 clouded. The mean cloudiness at 7 a. m. was 47.79 per cent.; at 2 p. 

 M., 48.06 per cent.; at 9 p. m., 36.99 per cent. 



WIND. 



During the year (three observations daily), the wind was from 

 the south 255 times, northwest 235 times, north 130 times, southwest 

 1 16 times, southeast 106 times, east 95 times, northeast 88 times, west 

 51 times, calm 22 times. 



It will be seen that the south winds (including southwest, south 

 and southeast), outnumbered the north winds (including northwest, 

 north and northeast), in ratio of 477 to 453. This preponderance of 

 the south winds has existed in each of our five years of observation. 

 In New England, the north winds largely outnumber the south winds. 



Observations upon the velocity of the wind were made during 

 the second half of the year. During the six months, the anemome- 

 ter on the north dome of the University building, registered 64,828 

 miles as the entire distance traveled by the wind. This gives an 

 average hourly velocity of 14.68 miles. The average at Philadelphia 

 is 13 miles an hour. 



The highest velocity during the six months was 60 miles an hour, 

 from 9 A. M. to 3 p. M., November 14th, on which day the wind 

 traveled 1,050 miles. 



BAROMETER. 



Mean height of barometer column, 29.112 inches. Mean at 7 A. 

 M., 29.137 inches; at 2 p. m., 29.089 inches; at 9 p. m., 29.1 ii inches. 

 Maximum height, 29.779 inches, at 9 p. m., November 28; minimum, 

 28.401 inches, at 2 p. m., April 6; range for the year, 1.378 inches. 

 The highest monthly mean was in December, 29.299 inches; the 

 lowest was in April, 28.999 inches. 



RELATIVE HUMIDITY. 



Mean for the year, 64.4, that is, the air contained on the average, 

 |ess than two-thirds the amount of moisture necessary for saturation. 



