NATURAL PHILOSOPHY. 



PAGE'S EXPERIMENTS ON ELECTRO-MAGNETISM. 



CONGRESS, it is well known, some time since made an appropriation 

 to enable Professor Page, of Washington, to test upon an extensive 

 scale the applicability of electro-magnetism as a motive-power. From 

 the reports published in the National Intelligencer, and from other 

 sources, we have prepared the following abstract of those results ob- 

 tained by Professor Page which have as yet been made public. 



It is known that, when a helix of suitable power is connected with 

 the poles of a battery in action, an iron bar within it will remain held 

 up by the induced magnetism, although the helix be put in a vertical 

 position ; and if the bar be partially drawn out of the helix by the 

 hand, it goes back with a spring when left free again. This power, 

 the action of the helix upon the metallic bar within it, is the power 

 used in Professor Page's engine. The power, when a single coil is 

 used, has its points of greatest and weakest force, and in this condition 

 is objectionable. But, by making the coil to consist of a series of 

 short, independent helices, which are to be brought into action succes- 

 sively, the metallic rod is made to pass through the coil and back 

 again with great rapidity and with an equable motion. In all the 

 engines hitherto used, there is a loss of power at the instant of the 

 change of current, owing to the production of a secondary current 

 moving in an opposite direction, and this loss is the reason why these 

 engines cannot be rendered available. Professor Page had in view 

 the obviating of this difficulty when he commenced his investigations, 

 and has had full success in his invention. 



The first principal experiments were made with a small trial-engine, 

 built expressly for the purpose, and with the utmost care in reference 

 to mechanical accuracy. Attached to this was a dynamometer of new 

 construction, which measured in a most satisfactory manner the dy- 

 namic power of the engine, at any given velocity, a great desideratum 

 in estimating this new power. With this trial-engine the following 

 important questions were tested : 1 . The dynamic values of different 

 qualities of soft iron. 2. Of steel, hard and soft. 3. Of cast-iron. (The 



