250 SCIENTIFIC RECREATIONS. 



the cover is removed. The writing will have a curious effect, but practice 

 will speedily remove all deficiencies. The same negative will serve for a 

 great many impressions, quite a thousand having been taken from one. By 

 people accustomed to such work as many as six proofs a minute may be 

 obtained. Of- course a little practice will be necessary in this, as in every 

 other case, before a correct or rapid result can be obtained, but there is no 

 difficulty in the practice. 



There are two or three other applications of electricity which we must 

 refer to ; such as the electric stamp, of which we give an illustration, and a 

 curious method of stopping a horse by electricity. The electric stamp 

 might be very advantageously employed in our post offices to obliterate the 

 " Queen's Head." The description, with illustration of this apparatus, is 

 annexed. (See fig. 261.) 



Fig. 260. Duplicating press. 



At the lower end of the apparatus is a thin platinum wire, so arranged 

 as to form either a design or an initial ; by this the postage stamp can be 

 defaced. The stamp being put in communication with the pile, the circuit 

 is closed by the pressure of the finger, as shown in the illustration. The 

 platinum grows heated and carbonises the paper, and thus proves itself an 

 ineffaceable stamp. 



This apparatus may easily be used, not only by the post office 

 authorities, but by every one who is obliged to deface a certain number of 

 stamps every day, and wishes to do so rapidly and without possibility of 

 error. 



An ingenious, if scarcely necessary arrangement for conquering restive 

 horses, and frightening them into submission, is shown in the illustration 

 (fig. 262). Many means have been tried to stop or conquer a restive horse, 

 but the most efficacious has been designed by M. Defoy; and the director of 



