40 REPORT—1852. 
heated or cooled, exists. Every substance is an assemblage of particles between which 
a definite distance exists, as shown by every body having a specific gravity and bulk 
always the same for the same temperature; and therefore the matter and space 
of a body are related, or have some dependence on each other. Now if two bodies be 
brought together at an insensible distance (and this must always be the case before 
chemical action takes place), they form, as far as their particles are concerned, one 
body; and therefore these particles behave as though they were particles of a simple 
body, that is, the distance between them or the space is regulated by the matter. 
But as the matter of the compound body is not the same as the matter of either of 
those separately which compose it, the distance between the particles of the compound 
must be different from that of the elements. This distance cannot be greater, for 
then the particles would be nearer at a sensible than an insensible distance, and so 
could not mix at all; and being less, a particle of each of the elements must be joined 
to one of the other, for if not, the relation of the space to matter could not be carried 
out: hence what is called chemical combination. And, as where two simple bodies 
are brought together they unite, if the distance of the particles is less for the compound 
than the simple, so, if a simple and compound body are mixed, the former decomposes 
the latter if its particles lie closer to those of either of the elements of the former than 
those of the other elements do, for in every case the relation between space and matter 
must be carried out. But in other papers published in the Philosophical Magazine, 
Dr. Woods has endeavoured to show that the distance between particles cannot either 
be increased or diminished without an opposite and equal change simultaneously 
occurring in some other particles; hence, when in chemical combination the distance 
between the uniting particles is being diminished, other particles expand, and this 
expansion is the heat of chemical combination: and the necessity of this equal and 
opposite movement shows that it cannot be any power of matter, such as attraction, that 
causes particles to cohere, but the absence of expansion going on in other bodies; and 
the same law also proves that the idea of repulsion is equally unnecessary. Now, accord- 
ing to this theory, bodies which have the greatest affinity for each other should also lie 
the closest together, and as the more closely they lie the greater the distance their parti- 
cles move together when combining, so the heat or accompanying expansion, which is 
equal although opposite, might be taken as a measure of the affinity of bodies for each 
other. 
To prove whether this idea were correct, the author investigated the “ amount 
of heat produced by the combination of several metals with oxygen.” The method 
of finding the amount of heat is new. Instead of burning the metals in oxygen, as 
formerly, Dr. Woods dissolved them in water (potassium, sodium), or sulphuric or 
nitric acid, and noted the effect on the thermometer. To the number of degrees 
indicated was then added the quantity of heat absorbed by the decomposition of the 
dissolving menstruum; for Dr. Woods has proved in the October Number of the 
Philosophical Magazine, 1851, that ‘‘ decomposition of a compound body absorbs as 
much heat as the combination of the elements originally produced.” In the follow- 
ing table are the results :— 
Amount of heat produced by the combina- 
Name of metal. tion of an equivalent of each with 1 grain 
of oxygen in 60 grains of water. 
ACID IN alareres cts shaeso cose licalon shes ace See ae 284-0 Fahr. 
MEAS SYUIMEL oas cay ey tinlals iors Lele B scusttte Sociale 2565. ,, 
HAN OEE OEE a taielitiefaladeiata tte bia 159°8_,, 
Tin wolgisiseksie a\p/aiSataiie<oia opeisiain ie Bos aad 
DTN SRS BS AES PES eee TL es 
A etre nisiéassunis aie iclatisieiafeiris alaidogts 99°4 ,, 
LS TET OIE aes in dag Zap mse piT Eee Nias 
WOPPEL caw ceccceccccen se ein aiajeloiein Ist aut alas 
WWGKE NEVE os)0 eoots 3 se SOOT Oe eee kN ae 
SULVETaie Gs </c%s.e'5,. Risin nats hk eeteiys 389 
On the Combination of Metals with Oxygen. By T. Woon, M.D. 


