242 Dr. J. Croll on the Transformation of Gravity. 



as effectually as cither heat or electricity ; and the energy 

 thus employed is as really and truly converted into mechanical 

 energy as was the heat or the electricity in the cases to which 

 we have referred. An electrical machine driven by water- 

 power will as effectually produce electricity as though it were 

 driven by steam-power or by horse-power ; and the electricity 

 produced will as truly be derived from gravity in the one 

 case as it would be from heat or from animal power in the 

 other cases. 



If then it be admitted, as it must be, that in the case of the 

 electricity produced by the machine driven by steam-power 

 the electricity previously existed under the form of heat, 

 for the same reason it ought to be admitted that the elec- 

 tricity produced by the machine when driven by water-power 

 previously existed under the form of gravity. 



We may now suppose the process reversed and electricity 

 to be the motive power. Conceive a machine of some kind 

 or other driven by electricity, and this machine to be employed 

 in the production of heat, say by friction, and to be employed 

 also in raising water. It will be universally admitted that we 

 have in the one case electricity converted into heat ; but it is 

 equally evident that we have in the other case electricity 

 converted into gravity. If the electricity produced by the 

 descent of the water be gravity transformed into electricity, 

 then the ascent of the water produced by electricity must be 

 electricity transformed into gravity ; for it is the same process 

 merely reversed. 



Gravity in relation to Conservation. — If gravity be corre- 

 lated to other forms of energy, it must, like them, come under 

 the great principle of conservation. But here we enter 

 upon debatable ground. It is admitted that gravity can 

 perform mechanical work, and the mechanical work can be 

 converted into other forms of energy. Here we have correla- 

 tions; but it is generally denied that there is a decrease or loss of 

 gravity resulting from such transformations. But this appears 

 to me to be a virtual denial of the principle of conservation. 

 To suppose a steam-engine to perforin the work of raising the 

 loaded piston, without the steam sustaining any loss of heat, 

 would be universally admitted to be a violation of the prin- 

 ciple of conservation. Every one would maintain such a 

 thing to be impossible, and that the steam must not simply 

 lose heat but lose an amount equivalent to the work performed. 

 Apply the same mode of reasoning to gravity. If gravity 

 perform mechanical work in pulling down the piston, then 

 there must be a loss of that form of energy equivalent to 

 the work performed, But it is not admitted that gravity is 



