318 SCIENTIFIC BALLOONING. 



visual observations of any scenes below, viz, the haze that veils the 

 lower levels from the traveler aloft. This is a true physical fact, and 

 due to the particles of low-lying matter in suspension, which, present- 

 ing their sun-lit surfaces toward an observer above, create a glare to 

 his vision, while to another observer on the earth the same dust motes, 

 presenting only their shaded sides, do not betray their presence save 

 by somewhat diminishing the direct light of the sky. On one occasion, 

 when rising almost perpendicularly to a great height above the Crystal 

 Palace, with the sun bright overhead, dense white cloud wreaths 

 entirely obliterated the scene below, yet visitors in the Palace grounds 

 continued to watch the balloon, but half hidden in what appeared to 

 them only the thinnest summer cloudlet. 



Perhaps the most serious drawback to ballooning in our own country 

 is the very limited territory over which it can be practiced. A gale 

 blowing 60 or 70 miles an hour would render a voyager above the 

 clouds soon liable to be carried out to sea without his knowledge, and 

 unless he can see stationary objects below he is usually quite ignorant 

 of his rate of travel. He is, indeed, for the most part unconscious of 

 all wind or of any motion of his own vessel, until, with anchor cast 

 overboard, she at length strikes earth. It is then in rough weather 

 that delicate instruments are apt to take harm. It is then that fellow- 

 passengers, for mutual safety, must stick by their craft and hold on 

 well together. In other words, it is then that the fun begins. And 

 maybe, riding steeplechase with a cripple balloon, bowling over open 

 country before a stiff wind, yields little in excitement to a brush with 

 the Pytchley. 



Such, however, must be considered record occasions. The more 

 common experience on descending is to approach the earth with an 

 onward flight no faster than pursuing peasants can run. Speed in 

 general is in proportion to elevation. On the occasion just referred 

 to, the balloon in question remained hovering over the Crystal Palace 

 grounds, and apparently over the same spot in the grounds, for some 

 twenty minutes, till, as altitude increased, the whole inclosure had, to 

 all appearance, shrunk together to the dimensions of a toy model, 

 when the balloon began to draw away at a steadily increasing rate, and 

 reached Bainham in Essex at an average speed of 7 miles an hour. 



To pursue aerial travel at its best it will perhaps be agreed that a 

 height not exceeding 3,000 or 4,000 feet will be most convenient, but it 

 must be remembered that a balloon never maintains for long the same 

 altitude. Reaching regions of less atmospheric pressure, and other 

 conditions remaining the same, a portion of gas escapes, causing the 

 balloon to descend until checked by discharge of ballast, when it again 

 changes its motion, and like an unsteady balance, oscillates above and 

 below its true level of equilibrium. 



For eye observations of earth no higher altitudes need be desired. 

 Clouds not intervening, the distance for 30 miles will often be distinctly 



