308 LETTERS ON NATURAL MAGIC. 



The difficulty, however, really consists 'in sustaining the 

 anvil, for when this is done the effect of the hammering 

 is nothing. If the anvil were a thin piece of iron, or 

 even two or three times heavier than the hammer, the 

 performer would be killed by a few blows ; but the blows 

 are scarcely felt when the anvil is very heavy, for the 

 more matter the anvil has, the greater is its inertia, and 

 it is the less liable to be struck out of its place ; for 

 when it has received by the blow the whole momentum 

 of the hammer, its velocity will be so much less than that 

 of the hammer, as its quantity of matter is greater. 

 When the blow, indeed, is struck, the man feels less of 

 the weight of the anvil than he did before, because in the 

 reaction of the stone all the parts of it round about the 

 hammer rise towards the blow. This property is illus- 

 trated by the well-known experiment of laying a stick 

 with its ends upon two drinking glasses full of water, 

 and striking the stick downwards in the middle with an 

 iron bar. The stick will in this case be broken without 

 breaking the glasses, or spilling the water. But if the 

 stick is struck upwards as if to throw it up in the air, 

 the glasses will break if the blow be strong, and if the 

 blow is not very quick, the water will be spilt without 

 breaking the glasses. 



When the performer supports a man upon his belly as 

 in Fig. 54, he does it by means of the strong arch formed 

 by his backbone, and the bones of his legs and thighs. If 

 there were room for them he could bear three or four, or, 

 in their stead, a great stone, to be broken with one blow. 



A number of feats of real and extraordinary strength 

 were exhibited about a century ago, in London, by 

 Thomas Topham, who was five feet ten inches high, and 

 about 31 years of age. He was entirely ignorant of any 

 of the methods for making his strength appear more 

 surprising, and he often performed by his own natural 



