22 Soap Bubbles. 



by Graham, who, like other great pioneers of science, attacked 

 the most abstruse problems with the simplest possible apparatus. 

 I think I have seen it stated that his entire laboratory for his 

 diffusion experiments was contained on an old tea tray, and 

 consisted of a few glass tubes, phials, and tobacco-pipe stems, 

 and some plaster of Paris. After all, as in the case of the 

 astronomical telescope, it is the man at the small end that is of 

 most importance. If an air bubble be placed in ether vapour 

 for a few seconds, the vapour diffuses into the bubble in suffi- 

 cient quantity to cause it to explode with a considerable burst 

 of flame when taken out and applied to a light. The magnetic 

 qualities of gases are conveniently studied when these are enclosed 

 in bubbles. Although outside the domain of bubbles proper, one 

 or two illustrations may be given of the beautiful geometrical 

 forms produced by Plateau on wire frames after immersion in 

 soap solution. A cubical frame shows an arrangement of one 

 rectangular film in the middle joined to the corners by twelve 

 trapezoidal films. A triangular prism gives a set of nine plane 

 films, and a helice of wire gives a very pretty screw-shaped 

 film. A frame consisting of three rings fixed to a centre forms 

 a circular trough of soap films, round which bubbles may be 

 rolled as the ball on a roulette table. The greater part of these 

 experiments have been devised by Mr. C. V. Boys, A.R.S.M., 

 of South Kensington Science Schools, and are described in a 

 recent number of the Philosophical Magazine, where also he 

 gives the ingredients of the solution used in forming the 

 bubbles. Some are from other authors, and others have been 

 devised specially for this evening. 



In conclusion, it may be asked — Cui bono ? What is the 

 good of it all ? The seeker after knowledge asks no further 

 result or reward than the pleasure of attaining definite know- 

 ledge. As the artist loves beauty, and will create beautiful 

 forms for the mere love of his art, so the philosopher finds his 

 keen pleasure in acquiring and setting in order new forms of 

 knowledge. There is a keen delight in a new successful origi- 

 nal experiment that belongs to few other enjoyments — in see- 



