STUDIES ON THE PHENOMENA. OF CONTACT. 411 



it is the cause of the latter, just as we sometimes see electricity excited, without 

 being able to assign to this electricity a chemical origin. 



We may say that in every case, without exception, an electric current may 

 determine the combination or the decomposition of bodies, and polaritij seems 

 to be an indispensable condition, in order that chemical action should manifest 

 itself. Chemical affinity cannot be regarded as the cause of the polarity ; 

 polarity cannot be regarded as the cause of the affinity. When, in heating a 

 plate of bismuth soldered to a plate of antimony, electricity is produced, 

 what is the cause of its production 1 Is it in the affinity of the bismuth for 

 the antimony ] Certainly not ! Is it in the heat 1 We enter here upon con- 

 siderations of a very high order, and which it is not competent for us to discuss 

 on this occasion. Let us say, however, a few words respecting them. 



In all that has been said, we have employed the term force. Although 

 it be now nearly demonstrated that nearly all force is but a molecular move- 

 ment, and that, consequently, the idea Avhich we generally attach to the word 

 force is inexact, yet the epoch has not arrived when we can suppress these 

 terms in the language of science, and, at the same time, make ourselves intel- 

 ligible. I have thus found myself compelled to employ them. In the remark- 

 able theory of M. Grove on the correlation of physical forces, things are 

 considered, according to all probability and verisimilitude, under their true 

 point of view. Movement, Avhich is universal, manifests itself to us sometimes 

 under one form, sometimes under another, in order to give rise to effects which 

 Ave arc in the habit of attributing to particular forces. These forces, or, rather, 

 these movements, may be transformed into other equivalent movements, 

 according to the circumstances in which they are made to act. Thus it 

 is that if We apply friction (movement) to a jDicce of dry wood, it is transformed 

 into another movement which we call heat. If we apply friction to sealing-wax, 

 the friction (movement) is transformed into current electricity. If we heat 

 water a large quantity of the heat is transformed into a motive force, into 

 movement. If Ave heat a plate of bismuth soldered to a plate of antimony, the 

 heat is transformed into current electricity. In like manner, heat is transformed 

 into light, light into heat, into electricity, into affinity, &c.; affinity into heat, into 

 electricity, into light, &c., &c. There exists no "force" Avhich Ave cannot 

 transform, equivalent for equivalent, into one or sCA^cral other "forces." These 

 transformations are manifested throughout all nature, and Ave see Avliat Ave call 

 "physical and chemical forces" transformed into "organic forces," and gov- 

 erning the phenomena of life. Just as atoms combine or replace one another 

 by equi\-alents, so are different movements or "forces" substituted, one for 

 another, equivalent for cqtdralent. A given quantity of chemical action Avill 

 ahvays give the same quantity of electricity ; a given quantity of electricity 

 Avill, in its turn, give the same quantity of chemical action ; a given quantity 

 of heat Avill always give the same quantify of motive force; an equi\-aleut of 

 chemical action Avill always give an equivalent of heat, &;c., &c. 



In fine, CA-erything is connected or linked together in nature; move- 

 ment, like matter, is universal ; its modificat'ons produce all that we regard as 

 "forces" or effects of forces. For the details and experiments on which this 

 striking theory is based, (and it is now admitted by most physicists,) we must 

 refer our readers to the memoir of M. Grove,* of Avhich avc have a French 

 translation from the learned pen of M. F. Moigno. But, from the few Avords 

 Avhich have been said, it Avill, I think, be conceived hoAV heat can act to excite 

 polarity and chemical action ; hoAv the latter, in its turn, can excite polarity and 

 heat, without one of these "forces" being the cause, properly speaking, of the 

 other ; how the movement of the barbs of a quill can act so as to produce 

 explosion with fulminating powders, &c. 



* Correlation of physical forces. 



