18 Things not generally Known. 



the inhalation is completed, we close the rima glottidis to keep 

 the air in the lungs. The chest being thus kept expanded, the 

 pulling or lifting muscles have received as it were a fulcrum 

 round which their power is exerted ; and we can thus lift the 

 greatest weight which the muscles are capable of doing. When 

 the chest collapses by the escape of the air, the lifters lose their 

 muscular power; reinhalation of air by the liftee can certainly 

 add nothing to the power of the lifters, or diminish his own 

 weight, which is only increased by the weight of the air which 

 he inhales." 



" FORCE CAN NEITHER BE CREATED NOR DESTROYED." 



Professor Faraday, in his able inquiry upon " the Conserva- 

 tion of Force," maintains that to admit that force may be de- 

 structible, or can altogether disappear, would be to admit that 

 matter could be uncreated; for we know matter only by its 

 forces. From his many illustrations we select the following : 



The indestructibility of individual matter is a most important case of 

 the Conservation of Chemical Force. A molecule has been endowed with 

 powers which give rise in it to various qualities ; and those never change, 

 either in their nature or amount. A particle of oxygen is ever a particle 

 of oxygen ; nothing can in the least wear it. If it enters into combina- 

 tion, and disappears as oxygen ; if it pass through a thousand combina- 

 tions animal, vegetable, mineral ; if it lie hid for a thousand years, and 

 then be evolved, it is oxygen with the first qualities, neither more nor 

 less. It has all its original force, and only that ; the amount of force 

 which it disengaged when hiding itself, has again to be employed in a 

 reverse direction when it is set at liberty : and if, hereafter, we should 

 decompose oxygen, and find it compounded of other particles, we should 

 only increase the strength of the proof of the conservation of force ; for 

 we should have a right to say of these particles, long as they have been 

 hidden, all that we could say of the oxygen itself. 



In conclusion, he adds : 



Let us not admit the destruction or creation of force without clear 

 and constant proof. Just as the chemist owes all the perfection of his 

 science to his dependence on the certainty of gravitation applied by the 

 balance, so may the physical philosopher expect to find the greatest 

 security and the utmost aid in the principle of the conservation of force. 

 All that we have that is good and safe as the steam-engine, the electric 

 telegraph, &c. witness to that principle ; it would require a perpetual 

 motion, a fire without heat, heat without a source, action without re- 

 action, cause without effect, or effect without cause, to displace it from 

 its rank as a law of nature. 



NOTHING LOST IN THE MATERIAL WORLD. 



"It is remarkable, 1 ' says Kobell in his Mineral Kingdom, 

 " how a change of place, a circulation as it were, is appointed 

 for the inanimate or naturally immovable things upon the earth ; 

 and how new conditions, new creations, are continually deve- 

 loping themselves in this way. I will not enter here into the 



