OF ARTS AND SCIENCES. 133 



being about one eighth of an inch in length. The sky was perfectly 

 cloudless at this time. As the kite remained very steady, it was 

 fastened, and allowed to remain up until near eleven o'clock. The 

 deflection of the needle was observed at frequent intervals, and the 

 needle then brought back to the zero by connecting with the ground. 



At eight p. M. the kite was more to the northeast than befoi'e, but 

 at about the same elevation. The deflections, however, were much 

 less than during the rest of the day, and for the most part within the 

 scale limits. The needle kept constantly moving, but with little of the 

 vigor it had previously shown. The character of the deflections may 

 be illustrated by the following record for a single minute : — 



Time. „ ^ . „, ^ Equivalent ia 



Junel9.1S85,P.M. Deflection. Character. ^^j^^ ^^ 



h. m. 8. 



8 4 24-1- Steady. Over 500 



10 10 Variable. " 200 



20 8 Decreasing steadily. " 150 



30 15 Very variable. " 300 



40 15 < Variable, increasing) „ ^^ 



( and decreasing. ) 



50 8 to 15 Variable. " 150 



8 5 10 " 200 



The movements of the kite at this time appeared to be very slight, 

 and one would be apt to suppose too small to account for the great 

 potential changes. But it must be noticed that the movements of the 

 kite, as far as they could be made out, were always in the proper 

 direction to correspond with the character of the potential chano-es ; 

 that is, a rise in the position of the kite was attended with an increas- 

 ing potential, and a fall attended with a decreasing potential. 



At 8 h. 20 ra. the deflection was very steady in character, and about 

 18. The potential indicated by that deflection was not sufficient to 

 give a spark. Fifteen minutes later fair-sized sparks could be obtaiued 

 at very short intervals. At nine o'clock the same condition prevailed. 

 At ten o'clock the sparks were larger and more frequent. The sky 

 during the whole time was cloudless. 



The morning of June 19 was cloudless but hazy, and there was not 

 sufficient wind to fly the kite. In the late afternoon, the wind having 

 freshened from the southwest, the kite was raised to an elevation of 

 about 500 feet above the summit. The kite remaining steady, the 

 deflection was beyond the range of the instrument, and evidently 

 greater than had yet been obtained. Largo sparks could be obtained 

 every few seconds by presenting the ground-wire to the kite-wire. 



