208 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



The great event of the year in the application of aeronaut- 

 ics to meteorology has been the success of Giffard's giant 

 captive balloon. This balloon has proved, as far as is known, 

 perfectly manageable, and has made from two to twenty as- 

 censions on every pleasant day, carrying up each time about 

 forty persons (among them always a meteorological observer). 

 The revenue derived from it lias more than paid the orig- 

 inal cost of the apparatus. A complete description of the 

 balloon has been published by Tissandier, extracts from 

 which have been published in numerous periodicals. The 

 diameter of the inflated gas-bag is 36 meters; it was inflated 

 with pure hydrogen made by the action of sulphuric acid on 

 iron. The balloon is confined by a cable 660 meters long. 

 The material of which the o-as-bao; is made has shown itself 

 capable of retaining the hydrogen with scarcely any loss 

 during four months. So complete has been Giffard's success 

 that the Abbe F. Moigno, editor of Les JHondes, asserts that, 

 had he been properly encouraged ten years ago by the 

 French government, the investment of Paris could never 

 have been completed, and the payment of five milliards need 

 never have been forced upon France. 



The receipts during the first 60 days exceeded 8100,000, 

 which was about the original cost of the balloon. In the 

 beautiful weather of the commencement of October, the bal- 

 loon accomplished between 8 A.M. and 6 P.M. 2-1 consecu- 

 tive ascensions, so that in a single day 900 persons ascended 

 and descended. The captive balloon is a veritable aerial 

 sounding-line, and continually reveals the existence of super- 

 imposed currents which escape the observer on the ground. 

 One is frequently plunged, at an altitude of 100 or 200 me- 

 ters, into rapid currents, while the air is calm below ; some- 

 times, on the contrary, the balloon is becalmed while strong 

 winds prevail at the earth. 



The Giftard balloon has been lately sold to a London 

 company, and will be removed thither; while a new and 

 larger one will be built to replace it in Paris. 



Aeronautic ascensions were made from Paris, June 30 and 

 July 2, in small balloons of only 450 cubic meters, or less 

 than 14,000 cubic feet, bat filled with hydrogen gas. Ac- 

 cording to Nature, it was on these occasions noticed that cu- 

 muli have a height sometimes twice as cn-eat as their liori- 



