FOR HIGH LEVELS IN THE EARTH S ATMOSPHERE. 



63 



Because of our ignorance of these rules I have in the succeeding calculations interpo- 

 lated to 8 A. M. only those observations ol)tained from ascents between 6 A. M. and 

 11 A. M. 



The extrapolation of the observations to 8 A. M. or to 8 P. M. and the calculation 

 of the values of the four quantities !!['■, jJy, EjJ^, Vp, can be most advantageously per- 

 formed by the kite-observers immediately upon reeling in the kite. The results may 

 be readily concentrated to two or three numbers and thus easily telegraphed to the 

 Central Office. As an illustrative example I proceed to show how the kite-ascension at 

 Omaha, Nebr., on 23 Sept., 1898, should be worked up. In Table 14 the figures for 

 pressure (p), temperature (t), and relative humidity (r), are taken from the corre- 

 sponding curves of the self-recording meteorograph at the kite, while the heights (/i) 

 are calculated trigonometrically from the length of the kite-line of steel wire and the 

 angular elevation of the kite. The values of tr are deduced from jJ, t and r ; and the 

 values of V from the observed elevations, in the manner already described. 



Table 14. 

 Kite Obsebvations with the Values of tr and V, at Omaha, Sept. 23, 1898. 



Using the values of tr in Table 14, as abscissae and the corresponding values of V 

 as ordinates, the points in Fig. 1 are plotted and then a curve drawn through them 

 which gives the values of tr at the elevation of every level surface of gravity both for 

 the ascent and the descent, by direct reading. By the aid of this {tr, F)-curve and 

 the observations made at 8 A, M. at the station, the observer or kite official should 



* 75th meridian time or l' 24" faster than Omaha local mean solar time. 



