EECEEATIVE SCIENCE. 



173 



LATENT HEAT SUDDENLY MADE SENSIBLE. 



It is a common trick among boys to rub 

 a brass button rapidly upon a smooth piece 

 of wood, and tben to apply it to a com- 

 panion's cheek ; the button being then " too 

 warm to be pleasant," induces some merri- 

 ment at the expense of the luckless wight 

 who is the victim of it. The heat thus pro- 

 duced is a simple example of frictional heat. 

 A somewhat similar experiment, illustrating 

 the latent heat of amorphous antimony, leads 

 us to a branch of " recreative science." 



The slightest friction against a piece of 

 this antimony makes it instantaneously " too 

 hot to hold." If a small tube of amorphous 

 antimony, like a test-tube, be filled with cold 

 water, and then the tube be abraded with a 

 file, so much heat will be given out that the 

 water will boil. Small pieces of amorphous 

 antimony held between the thumb and finger, 

 and rubbed on any rough surface— the file 

 of a pair of nail-scissors will do— becomes so 

 suddenly hot, that the efi'ect "seems like 

 magic." 



Mr. Gore, of Birmingham, discovered 

 amorphous antimony. The following is his 

 process for making it :— " Take two parts of 

 hydrochloric acid, add as much oxide of an- 

 timony as it will dissolve with much stirring, 

 and then add one more part of acid. Now 

 pass a current of electricity from a small 

 battery through the solution by means of an 

 anode of antimony and a cathode of sheet 

 copper ; continue the action for two or three 

 days, until the antimony is deposited upon 

 the copper from one-sixteenth to one-eighth 

 of an inch thick ; then transfer the copper 

 cathode to a bowl of cold water, bend it 

 cautiously, and the amorphous antimony will 

 drop ofi" in flakes. When dried, it may be 

 kept in wool any period for future " recrea- 

 tion." 



A BEOWN-PAPEE MAGNET. 



A very simple and interesting electrical 

 experiment may be made with a sheet of 



brown paper, illustratmg, in a remarkable 

 manner, how the most astonishing effects 

 may be produced by the simplest means. 

 Take a sheet of coarse brown paper, and 

 after holding it before the fire till it is per- 

 fectly dry, fold it up into a long strip of 

 about two inches wide ; the magnet is now 

 complete. To exhibit its attractive power, 

 cut some strips of writing-paper about three 

 inches long, and as wide as the space be- 

 tween these lines; place them upon the 

 table three or four together. Now take the 

 magnet, and draw it briskly under the arm 

 two or three times ; its electro-magnetism is 

 instantly developed, and becomes apparent 

 when held over the small strips of writing- 

 paper, for they fly up from the table towards 

 the paper magnet, veritably "by the wings of 

 lightning." 



EOSIN BUBBLES 



The method of making soap bubbles is 

 sufficiently familiar not to need description. 

 Eosin bubbles are made in a similar manner. 

 A tobacco-pipe is to be dipped into melted 

 rosin not hotter than just to liquefy it ; when 

 the pipe is blown through, bubbles will be 

 formed of various sizes, from that of an egg 

 down to a bead; and from their metallic 

 lustre and reflection of the different rays of 

 light, showing the prismatic colours, they 

 have a very pleasing appearance. They gene- 

 rally assume the form of a string of beads, 

 many of them perfectly regular, connected 

 by a gossamer fibre of rosin. Unlike soap 

 bubbles, those made in this way have suffi- 

 cient permanence to bear touching with a 

 gentle hand, and with care will remain per- 

 fect from Christmas-eve to Twelfthtide. 



TO LIGHT A CANDLE WITHOUT TOUCHING 

 THE WICK. 



Let a tallow candle burn until it has a 

 good long snuff, then blow it out ; with a 

 sudden puff a bright wreath of white smoke 



