McCOSH IN REPLY TO CARPENTER. 2 i 



those which are by many still considered to produce the most per- 

 fect of hammered work, the "wiper" was so shaped as to throw the 

 hammer very high. The ascent was checked by a powerful spring, 

 and thus the ascensional energy was reversed and added to the accel- 

 erating force of gravity downward; and so not only was the intensity 

 of the blows increased, but their frequency also. This spring took 

 the place of that muscular energy which brought the hammer down 

 w T ith intensified effect. 



Hence, also, in steam-hammers, all muscular effect to intensify the 

 blow is transferred to the steam, and all consequences of centrifugal 

 action, whether from hand or tilt hammers at the ends of arms, are 

 removed. Further, in steam-hammers nowadays, the steam operates 

 to check as well as to intensify the blow. This checking action is 

 called " cushioning," and it seems to do what an elastic handle does 

 in a sledge-hammer: it relieves the rigid fabric or erection from jar 

 or destruction. " Cushioning " is brought into play by admitting steam 

 for the purpose of checking the intensity of the blow due to the action 

 of gravity alone, or of steam combining with gravity upon the ham- 

 mer. Hence the perfect control over large steam or air worked ham- 

 mers, and the rapidity with which the intensity of the blow may be 

 changed. Such control as this over a sledge-hammer is beyond our 

 bodily powers. We may intensify the blow, but we cannot, except 

 just experimentally, and for the purpose of display, bring the restrain- 

 ing power of the muscles to diminish the energy of the descending 

 hammer. Journal of the Society of Arts. 



-+++- 



PREPOSSESSIONS FOR AND AGAINST THE SUPER- 

 NATURAL. 



A CRITICISM OF DR. CARPENTER. 

 By JAMES McCOSH, LL. D., 



PRESIDENT OF PRINCETON COLLEGE. 



DR. CARPENTER is master of the domain which he has appropri- 

 ated for the last age, that of physiology. He has done more than 

 any living man, not exactly to advance, but to combine and expound, 

 the discovered truths of his science. But he is ever impelled by his in- 

 tellectual sharpness and his cultivated tastes to take excursions into 

 other regions, and I am not sure whether he has there been so success- 

 ful. In particular, as dwelling so near the territory of mind, he has ever 

 been crossing into it. He has made a very careful survey of the bor- 

 der-country, and given us the result in his valuable work "Mental 

 Physiology." Ever since the palmy days of mesmerism and table- 



