438 NATUKES TEACHINGS. 



height of the ascent depend much on the wind and character of 

 the atmosphere. 



The web ascends because it is for the time lighter than the 

 atmosphere. But, as it gradually becomes laden with the 

 moisture that more or less fills the air, it becomes heavier than 

 the atmosphere, and gently sinks to the ground. 



What maybe the object of these aerial voyages no one knows. 

 They may be for the purpose of capturing minute insects, or 

 they may be for mere amusement. But in either case they are 

 highly instructive, as showing the principle on which the balloon 

 was framed. 



The little Grossamer Spider is shown on the left hand of the 

 illustration, clinging to its floating web. I believe that the 

 Gossamer is not a single species of Spider, but that there are 

 many species which deserve the name, being able to float in the air 

 when they are small, but losing that capacity as they increase 

 in size and weight. 



Now we come to another branch of the same subject, namely, 

 the safe descent from a great height by means of the Parachute. 



On the right hand of the illustration is the ordinary Para- 

 chute as it appears when open and closed, in either case having 

 somewhat the appearance of a large umbrella. It is hung to 

 the balloon in its closed state, and when detached it falls 

 rapidly for a yard or two with startling rapidity. The pressure 

 of the air thus forces the ribs open, and gives sufficient assist- 

 ance to the atmosphere to insure a gentle fall. 



On one memorable occasion, when the late Albert Smith was 

 in the car of a balloon upwards of a mile from the ground, the 

 balloon burst. Fortunately it burst so completely, that the 

 silk was driven into the closely meshed netting, and formed an 

 extemporised parachute, which took the voyagers to the earth 

 with safety, except some rather severe bruises. 



Children often amuse themselves with miniature parachutes. 

 They take a square piece of thin paper, tie threads to the four 

 corners, and then bring the ends together, a cork taking the 

 place of the car. They then launch it from a high window, 

 and should there be a favourable breeze, it is wonderful how far 

 it will be carried before it comes to the ground. 



Once, when a boy of eleven, and consequently thoughtless, 



