52 Kansas academy of science. 



THE CUEVE OF MEAN DAILY TEMPERATURES AT LAWRENCE, KAN- 

 SAS, FOE TWENTY-ONE YEAES, 1868-1888. 



BY PROF. F. H. SNOAV, OF THE UNIVERSITY OF KANSAS. 



The accompanying diagram represents the curve of normal daily mean tempera- 

 tures for 21 years. Upwards of 23,000 observations of Green's standard thermome- 

 ters are condensed in this curve, the instruments having occupied the same shelter 

 during tlie entire period of observation. An examination of this curve reveals the 

 fact that the 8th day of January is, upon the average, the coldest day in the year, 

 with mean temperature 18.04°; while the 15th of July is the hottest day, with mean 

 temperature 81°. The coldest period in the year — the very heart of winter — is 

 seen to be the 33 days from the 23d of December to the 24th of January, and the 

 hottest period in the year — the highest heat of summer — is the 31 days from the 

 2d of July to the 1st of August. 



A remarkable rise in temperature takes place from the 20th of March to the 4th 

 of April, the mean temperature increasing from 37.58° to 52.15°, or nearly 15°, in 15 

 days. This corresponds with the average time of blossoming of our fruit trees — 

 peaches, plums, pears, and early apples. 



A still more remarkable change in temperature takes place from the 7th to the 

 18th of November, the mean dropping from 49.67 to 33.70 degrees, or nearly 16°, in 

 11 days. This corresponds with the time when our base-burners, furnaces and other 

 permanent heating apparatus are put into operation for the winter's campaign. 



The real winter, kowever, may be considered as beginning on the 15th of Decem- 

 ber, when the mean daily temperature falls below the freezing point, not to rise 

 above that point until February 15, making the average winter exactly two months 

 in duration. 



In like manner the real summer may be regarded as extending from the 17th of 

 June to the 28th of August, this being the entire period during which the mean daily 

 temperature remains above 75°. If, however, we consider summer heat to include 

 the period whose average temperature exceeds 70°, the summer season will embrace 

 the three and a half months from May 26 to September 8. 



The remarkable fall in temperature from the 7th to the 18th of November would 

 seem to dispose of the theory that the contact of the earth with the November mete- 

 ors results in a marked increase in temperature of the earth's atmosphere. 



