METEOROLOGY. 387 



Some of the results of the observations made from the two balloons 

 sent up from the Crystal Palace, London, on Thursday, October 31^ 

 1880, are as follows : The direction of the wind was remarkably steady, 

 as during the run the two balloons were constantly kept in view of each 

 other in spite of the want of light and of aerial transparency. This result 

 is all the more to be noted that the variations in the altitude of the two 

 balloons were frequent and considerable, 10 to 5,000 feet. The varia- 

 tion of temperature did not amount to more than 5° C. between the 

 maximum of the readings and their minimum. A peculiar current was 

 observed just on arriving on the coast, which is usual under such cir- 

 cumstances. The composition of the clouds was very complex. First a 

 layer of transparent fog covered almost the whole of the land and gave 

 a watery aiDpearance to it ; second, cumuli described as analogous to 

 jmlled bread were floating at a height of 1,000 meters and descended 

 gradually as the sun was nearing the horizon; and, lastly, a large 

 number of parallel strati stretching southwesterly in the direction of 

 the sijn, and seemingly diverging from it. The velocity of the wind 

 was about half a mile per minute, and pretty well determined by ob- 

 servers located in one of the two towers of the Crystal Palace. As to 

 the prognostication of the route, it was nicely done by Mr. Coxwell, 

 who told M. de Fonvielle that he should land between Portsmouth and 

 Winchester. A question arose between M. de Fonvielle and Commander 

 Cheyne about the bearing, the latter's compass liaviug been reversed 

 by an optical illusion, but the azimuth was given with great accuracy, 

 and the uncertainty between the two would not have lasted for a minute 

 if the iiossibility of the error could have been ascertained. The swing- 

 ing of the balloon round its axis was sufficient to prevent the use of a 

 new compass designed on purpose for aeronauts. {Wature, xxii, p. 615.) 



M. Jules Godard, the well-known aeronaut, has invented an electrical 

 waruer; when the balloon is descending an electrical bell is set in 

 operation; when it is ascending another bell riugs. This eflect is ob- 

 tained very simi)ly by a valve which is in equilibrium when the balloon 

 keeps its level, but is moved hy a slight wind. (A similar result is ob- 

 tained by the use of the horizontal balanced fan or vane introduced by 

 the writer in 1872 and 1881 in balloon ascents for the Signal Office.) 

 {Nature, August, 1881, xxiv, p. 340.) 



M. W. de Fonvielle, editor of L'Electriciie. and M. Lippmann, one of 

 his contributors, made a balloon ascent on July 2, 1881, shortly after 

 midnight. The descent took place near Eambouillet, at a quarter past 

 five, the distance traversed being 18 kilometers. Tlie ballonists carried 

 with them a small Plante accumulator with a special sfjfety electric 

 lamp constructed by Trouve, composed of a platinum wire inclosed in a 

 glass tube. While the apparatus did not weigh more than 1 kilogram, 

 it gave sufficient light for reading the barometer and thermometer, and 

 writing notes with accuracy. A special luminous compass for aeronauts 



