274 Wisconsin Academy of Sciences, Arts, and Letters. 



support a weight of 498 grains, so that 1,000 cubic feet will carry- 

 about 70 pounds weight, which is the displacement of a balloon of 

 less than 13 feet diameter. 



The balloon is allowed to rise at pleasure by means of a cord of 

 sufficient strength to support considerable more than its own weight, 

 of the desired length or height. The lateral motion, while rising, 

 will indicate the direction of the currents; the height is computed 

 at any time by its position. 



The principal apparatus will be that for recording the tempera- 

 ture and barometrical changes. This is done by a clock-work ar- 

 rangement carrying a strip of highly sensitised paper, with a regular 

 motion, so that the condition of both instruments is photographed 

 at each instant of time. The observation having commenced, it is 

 only necessary to note the time and corresponding altitude, and ob- 

 tain the corresponding phenomena when the apparatus is recovered. 

 Under favorable circumstances, the balloon may be brought to rest 

 at different altitudes, in order to give the instruments time to as- 

 sume local conditions. To the apparatus is attached a parachute, 

 so that the same may be recovered in case of collapse or other acci- 

 dent. I have thought some of adding a magnetic apparatus, but 

 have not had time to develop the idea. 



This might possibly throw some light on the possibility of aerial 

 navigation, and also be worthy of consideration in other respects. 



Hoping you will have an interesting and pleasant meeting, I 

 remain, most respectfully, your obedient servant, 



JOHN NADER. 



THIRD SESSION. 



July 11, 3.30 P. M. 

 Rev. H. M. Simmons read a paper on " The Social Organism." 

 Prof. Hailman delivered a lecture on "The Kindergartens " 

 Judge Allen then read a paper prepared by Dr. Mason, on tfie " Duty of the 

 State to its Unfortunate Classes." 

 Prof. Butler read a paper on "American Pre-Revolutionary Bibliography." 



FOURTH SESSION. 



7.30 P. M. 

 Prof. Jewell, of Chicago, read a paper on " Mind in the Inferipr Animals." 

 Academy adjourned to attend a reception given by Mayor Meacham in 

 honor of the members. 



