. Introduction to inorganic chemistry . en a current of electricity is runthrough the dynamo, motion results. Butthe most significant facts are still to be men-tioned. The heat absorbed by the motoris found to be greater when the machineis permitted to move and do work, thanwhen it is not. Thus, it is found thatwhen work is done some heat disappears,and is, in fact, transformed into , when the poles of the dynamo ai»e properly connectedand electricity is being produced, and only then, motion is usedup. This is shown by the effort required to turn the armatureunder these circumsta
. Introduction to inorganic chemistry . en a current of electricity is runthrough the dynamo, motion results. Butthe most significant facts are still to be men-tioned. The heat absorbed by the motoris found to be greater when the machineis permitted to move and do work, thanwhen it is not. Thus, it is found thatwhen work is done some heat disappears,and is, in fact, transformed into , when the poles of the dynamo ai»e properly connectedand electricity is being produced, and only then, motion is usedup. This is shown by the effort required to turn the armatureunder these circumstances, and the ease with which it is turnedwhen the circuit is open. So, with a conductor like the filamentin the lamp, unless it offers resistance to the current and destroysa sufficient amount of electricity, it gives out neither light norheat. Finally, motion gives no heat unless the brake is set, andeffort is then demanded to maintain the motion. These experienceslead us to believe that we have here a set of things which are funda-. FlG. 15. INTRODUCTORY II 26 mentally of the same kind, for each form can be made from any ofthe others. We have, therefore, invented the conception of a singlething of which heat, light, electricity, and motion are forms, and to itwe give the name energy: energy is work and every other thing whichcan arise from work and be converted into work (Ostwald). Closer study shows that equal amounts of electrical or mechanicalenergy always produce equal amounts of heat. There is never ob-served any loss in any of the transformations of energy any morethan in the transformations of matter. Hence, J. E. Mayer (1842),Colding (1843), and Helmholtz (1847) were led independently to theconclusion that in a limited system no gain or loss of energy is everobserved. This brief statement of the results of many experimentsis called the law of the conservation of energy. A current form of this law, namely, that the total amount of energy in theuniverse is a constant
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