158 Mr, W, /?. Grove^ on Negation of Perpetual Motion. 



If a battery of one cell, just capable of decomposing water and 

 no more, be emploj^ed, this will cease to decompose while making a 

 magnet. There must, in every case, be preponderating chemical 

 affinity in the battery cells, either by the nature of its elements or 

 by the reduplication of series, to effect decomposition in the vol- 

 tameter, and if the point is just reached at which this is effected, 

 and the power is then reduced by any resistance, decomposition 

 ceases : were it otherwise, were the decomposition in the voltameter 

 the exponent of the entire force of the generating cells, and these 

 could independently produce magnetic force, this latter force would 

 be got from nothing, and perpetual motion be obtained. 



In another case, cited by M. Matteucci, viz. that a piece of zinc 

 dissolved in dilute sulphuric acid gives somewhat less heat than 

 when the zinc has a wire of platinum attached to it, and is dissolved 

 by the same quantity of acid, the argument is deduced that as there 

 is more electricity in the second than in the first case, there should 

 be less heat ; but, as according to our received theories the heat 

 is a product of the electric current, and in consequence of the 

 impurity of zinc, electricity is generated in the first case molecularly 

 in what is called local action, though not thrown into a general 

 direction, there should be more of both heat and electricity in the 

 second than in the first case ; as the heat and electricity due to the 

 voltaic combination of zinc and platinum are added to that excited 

 on the surface of the zinc, and the zinc should be, as in fact it is, 

 more rapidly dissolved. Other instances are given by M. Matteucci, 

 and many additional cases of a similar description might be sug- 

 gested. But although it is difficult, perhaps impossible, to restrict 

 the action of any one force to the production of one other force, 

 and one only ; yet if the whole of one force, say chemical action, 

 be supposed to be employed in producing its full equivalent of 

 another force, say heat ; then as this heat is capable in its turn of 

 reproducing chemical action, and, in the limit, a quantity equal to 

 or at least only infinitesimally less than the initial force ; if this 

 could at the same time produce independently another force, say 

 magnetism, we could, by adding this to the total heat, get more 

 than the original chemical action, and thus create force or obtain 

 perpetual motion. 



The impossibility of perpetual motion thus becomes a valuable 

 test of the approach that in any experiment we may have made to 

 eliminating the whole power which a given natural force is capable of 

 producing ; it also serves, when any new natural phenomenon is dis- 

 covered, to enable us to ascertain how far this can be brought into re- 

 lation with those previously known. Thus when Moser discovered that 

 dissimilar metals would impress each other respectively with a faint 

 image of their superficial inequalities ; that, for instance, a copper 

 coin placed on a polished silver plate, even in the dark, would, after 

 a short time, leave on the silver plate an impression of its own 

 device, it occurred to Mr. Grove that as this experiment showed a 



