142 ANNUAL OF SCIENTIFIC DISCOVERY. 



20.0 ; at 20,000 feet, 19.5 ; at 25,000 feet, 16.3. Then the meastrre 

 of disturbance would be as follows : At 10,000 feet, 0.5 in excess; 

 at 15,000 feet, 8.3 in excess; at 19,500 feet, 22.2 in excess; at 

 20,000 feet, 13.5 in excess ; at 25,000 feet, 0.3 in defect. The num- 

 bers in the last column of the table show that the average decrease 

 of temperature in the first 5,000 feet exceeds 20, and in the next 

 5,000 feet is but little more than 10. The numbers in the lowest 

 line of the table show that the average decrease of temperature for 

 25,000 feet is 51 nearly. From these numbers it seems that two- 

 fifths of the whole decrease of temperature in five miles takes place 

 in the first mile, and therefore that the decrement is not uniform with 

 the increment of elevation. 



Mr. Glaisher then spoke upon the electrical state of the air, which 

 he found charged with positive electricity, decreasing in amount with 

 elevation. With respect to ozone, he said that none was shown in the 

 earlier ascents, but that large quantities were shown in the latter, and 

 attributed the deficiency in the former to bad paper. He remarked, 

 that diminished pressure exercised a very different influence upon 

 different individuals, dependent probably upon temperament and or- 

 ganization ; that the effect of high elevation was different upon the 

 same individual at different times ; that the time of vibration of a 

 magnet was somewhat longer at high elevation than on the earth ; 

 that different notes and sounds pass more readily through the air than 

 others, instancing that the barking of a dog can be heard two miles 

 high, and the shouting of a multitude not one mile. The author con- 

 cluded his paper with the following remarks : " These eight ascents 

 have led me to conclude, first, that it was necessary to employ a 

 balloon containing nearly ninety thousand cubic feet of gas ; and that 

 it was impossible to get so high as six miles, even with a balloon of 

 this magnitude, unless carburetted hydrogen, varying in specific 

 gravity from three hundred and seventy to three hundred and forty, 

 had been supplied for the purpose. It is true that these statements 

 are rather conflicting when compared with those made by one or two 

 early travellers who professed to have reached some miles in height 

 with small balloons. But if we recollect that at three and three- 

 quarter miles high a volume of gas will double its bulk, we have at 

 once a ready means of determining how high a balloon can go ; and 

 in order to reach an elevation of six or seven miles it is obvious that 

 one-third of the capacity of the balloon should be able to support the 

 entire weight of the balloon, inclusive of sufficient ballast for the 

 descent. 



" It has been stated by an aeronaut of experience that strong op- 

 posing upper currents have been heard to produce an audible conten- 

 tion, and to sound like the ' roaring of a hu?*ricane.' Now, the only 

 deviation we experienced from the most perfect stillness was a slight 

 whining noise in the netting, and this only when the balloon was rising 

 with great rapidity. The balloon itself, as it descends, flaps about oc- 

 casionally ; but this occurs when it is in a collapsed state, and very 

 likely it was under similar circumstances, and perhaps during a rapid 

 descent, that the flapping of the lower part of the balloon was mis- 

 taken for a roaring wind. I may also state that the too readily ac- 

 cepted theory as to the prevalence of a settled west or north-west 



