New Experiments with Soap Bubbles. 



there is no difficulty in blowing a bubble by means of a coal 

 gas supply (using a caoutchouc tube for connection), and attach- 

 ing the disc as before, detaching it from the pipe as soon as it 

 has attained a considerable ascending power. 



Under these circumstances it can be carried about at will, 

 floating in the air as high as the thread will allow, forming the 

 most delightful plaything that can be imagined. It is very 

 amusing to balance it by means of a considerable length of 

 thread, preserving a slight preponderance of the latter, so 

 that it slowly sinks. It may then be thrown towards the floor, 

 to which it descends until the excess of string rests upon the 

 ground, when the balloon remains gracefully suspended in the 

 air, waving about at each breath, without at all appearing to 

 suffer from its shackled condition. The unusual appearance of 

 such a balloon has a singular effect, which is increased if a 

 fibre of unspun silk be employed in the place of the visible 

 thread. In the same manner a car of silver foil can be attached 

 to the paper disc, and a miniature balloon ascent performed. 

 A balloon suspended in the above manner is a very sensitive 

 indicator of air currents. On this property a most interesting 

 experiment can be performed by placing in the middle of the 

 room a burning lamp, and bringing a balloon, nearly counter- 

 poised with excess of thread, within its influence, when it will 

 be slowly drawn towards the lamp, and will then immediately 

 ascend with the current of convection, as though it would be 

 dashed against the Ceiling 5 but not so, it will be carried round 

 by the current, after ah apparently hair-breadth escape, and 

 will descend in the stream of colder air, only to be again 

 dragged towards the lamp to perform the same round; 



These are only a few of the illustrations of natural laws 

 that may be obtained by means of our plaything; but the 

 above descriptions will enable the reader, if he care to repeat 

 them in a practical form, to devise many more, and to share 

 in the pleasure and instruction these experiments have afforded 

 the writer.* 



* The solutions whose preparation is described above may also be obtained of 

 Mr. Ladd, optician, Beak-street. 



