108 



KANSAS Academy of Sciexce. 



observer at the latter station, in the year 1876, noting the fact that the instru- 

 ment at Lawrence recorded more than twice as much wind as the Leavenworth 

 instrument, criticised the records of the University anemometer as palpably erro- 

 neous, fortifying the criticism by the statement that no other stations, except those 

 on Pike's Peak, Colorado, Mt. Washington, New Hampshire, and other high mount- 

 ain stations, could equal the records at Lawrence. In order to test the accuracy of 

 our records, Mr. John H. Long, of the class of 1877 of the Kansas University, now 

 the distinguished professor of chemistry in the Chicago Medical College, was induced 

 to make a thorough investigation of the question. The results of this investigation 

 are to be found in vol. VI of the Transactions of this Academy, pp. 87-89. Dr. Long 

 established the following facts regarding the University anemometer: 1st, That it 

 never registers too much; 2d, that for medium and high winds it makes a very close 

 approximation to the actual velocity; and 3d, that for small velocities it does not 

 register enough. This is due to the fact that a gentle breeze sufficient to give a 

 positive direction to a column of smoke will sometimes fail to move the cups for 

 many minutes. This instrument is after the English pattern, with cups nine inches 

 in diameter on arms twenty-four inches in length, and is connected with the record- 

 ing apparatus by a shaft whose upper and lower portions are of solid steel for a 

 distance of three feet, while the intervening portion consists of twenty-five feet of 

 three-fourths-inch gas pipe. The weight and friction of this shaft are sufficient 

 cause for the failure of the cups to readily respond to winds of less than five miles an 

 hour, and are also sufficient to more than overcome the twenty-per-cent. advantage 

 which, according to the English Professor Stokes, is possessed by this large type 

 of anemometer over the smaller instrument in use by the U. S. Signal Service, with 

 cups four inches in diameter on arms only seven inches in length. By the courtesy 

 of the Signal Service, I have had the use of one of these smaller anemometers 

 during the past year. This instrument has the same exposure as the larger instru- 

 ment, and has afforded another means of testing its accuracy. The following is a 

 comparison of the records of the two anenometers from March 10th to October 1st, 

 1888: 



Month. 



Larger Smaller 



Anemometer. Anemometer. 



March 



April 



May 



June 



July , 



August 



September., 



10, 130 miles. 9,522 miles. 



12,860 

 10,956 

 10,380 

 7,160 

 7,841 

 6,903 



Total. 



12,313 

 10,871 

 10,365 

 7,980 

 8,367 

 7,127 



66, 230 miles. 66,545 miles. 



From this tabular statement it appears that in March, April, May and June, in 

 each of which months the total run of the wind exceeded 10,000 miles, the larger in- 

 strument recorded respectively 608, 547, 85, and 15 miles more wind than the smaller 

 instrument; while in the calmer months of July, August and September the smaller 

 instrument outran the larger by 820, 526, and 224 miles. For the entire period in 

 which the comparison is made, the total register of the larger anemometer was 66,- 

 230 miles, and that of the smaller was 66,545 miles — giving a difference of only 315 

 miles in the total results. During the seven months included in this comparison, 

 occurred the highest wind ever recorded at Lawrence. Undoubtedly higher winds 

 have swept across the station; but such winds have disabled the apparatus, and pre- 

 vented a record. The greatest velocity ever recorded was on August 12th, 1888, in 

 the five minutes from 2:25 to 2:30 a.m., when by the smaller instrument eight miles 

 were registered, or at the rate of 96 miles an hour. The larger instrument registers 



