380 On the Temperaiure of a Bismuth and Antimony Joint. 



The length to which this paper has run prevents me remark- 

 ing on the foregoing table as fully as I would wish. It will be, 

 however, seen that those metals which are capable of displacing 

 others from neutral solutions produce more heat by their combi- 

 nation with oxygen ; or, according to tlie view I take of chemical 

 combination, require less distance between their particles and 

 those of oxygen than do the other metals. Thus when a salt of 

 silver in solution is pom-ed on copper, oxygen, silver and copper 

 are brought together at an insensible distance, mechanically for 

 the first instant forming one body, their particles lying together, 

 perfectly passive with respect to each other ; but as we deduce 

 from experiment that oxygen and copper lie more closely together 

 than oxygen and silver, the particles of the oxygen and copper 

 are exactly in the same predicament as a heated body v>'ould be 

 in conjunction with a colder one, the particles being separated 

 from one another to a distance greater than natui'al, so to speak, 

 for the mean temperature ; these particles therefore move toge- 

 ther or contract just as those of a heated body would do ; and 

 the particles of oxygen and silver which may represent the colder 

 body separate or expand to supply the opposite movement. 



It will be seen I do not attempt to explain ivhy copper and 

 oxygen lie more closely together than silver and oxygen in com- 

 bination. I merely say, that as their uniting is accompanied by 

 a greater expansion, or heat, in other bodies, and as that expan- 

 sion may be taken as equal and opposite to the contraction be- 

 tween the uniting bodies, those substances producing most heat 

 must lie more closely together; and that therefore all such hy- 

 pothetical ideas as electricities, subtle fluids, undulations, &c. 

 may be discarded in accounting for the heat of chemical combi- 

 nation ; and the movements immediately concerned in producing 

 it may be looked on as being in nothing different from those 

 where heat is given out from a simple body whose temperature 

 is more elevated than surrounding ones, except in this particular, 

 that a simple body whose temperature is raised loses its volume 

 to other bodies by an approximation of its own or similar par- 

 ticles, but in chemical combination it is tbe approximation of 

 diverse particles moving to unite. 



LX. On the Tempei-ature of a Bismuth and Antimony Joint 

 during the passage of an Electrical Current. By Richard 

 Adie, Esq. 



To the Editors of the Philosophical Magazine and Journal. 



Gentlemen, 



IN your Journal of 1st October, Dr. Tyndall has cited the ex- 

 periments of ]\I. Lcnz in proof of the power of a feeble gal- 

 vanic current to reduce the temperature of a bismuth and anti- 



