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same law which keeps all the planets, and the whole host of heaven in their 
respective places, and which must create in us more astonishment, that 
and augments the energy, of chemical agents. It is for this purpose that bodies are divided when they 
are to be analysed, and that the effect of re-agents is facilitated by the action of heat. 
The mechanical division of bodies is more difficult, the stronger their aggregation. 
Aggregates exist under different states; they are solid, liquid, or aeriform. 
OF THE AFFINITY OF COMPOSITION. 
Bodies of different kinds exert a tendency or attraction upon each other, which is more or less 
strong; and it is by virtue of this force that all the changes of composition or decomposition observed 
amongst them, are effected. 
The affinity of composition exhibits invariable laws in all the phenomena it causes. We may state 
these laws as general principles; to which may be referred all the effects presented to our observation 
by the action of bodies upon each other. 
Law I. The affinity of composition acts only between the Constituent parts of bodies. 
The general law of attraction is exerted upon the masses; and in this respect it differs from the law 
of affinities, which does not perceptibly act but on the elementary particles of bodies. Two bodies 
placed near each other do not unite; but, if they be divided and mixed, a combination may arise. We 
have examples of this when the muriate of soda, or common salt, is triturated with litharge; the 
muriate of ammoniac, or common sal ammoniac, with lime, &c. And it may be asserted, that the 
energy of the affinity of composition is almost always proportioned to the degree of the division of 
bodies. 
Law II. The affinity of composition is in the inverse ratio of the affinity of aggregation. 
It is so much the more difficult to decompose a body, as its constituent principles are united or 
retained by a greater force. Gases, and especially vapours, continually tend to combination, because 
their aggregation is weak: and nature, which is constantly renewing the productions of this universe, 
never combines solid with solid; but, reducing every thing into the form of gas, by this means breaks 
the impediments of aggregation; and these gases uniting together, form solids in their turn. 
Hence, no doubt, it arises, that the affinity of composition is so much the more strong as bodies 
approach nearer to the elementary state; and we shall observe, on this subject, that this law of nature 
is founded in great wisdom: for if the force of affinity of composition did not increase in proportion as 
bodies were brought to this degree of simplicity; if bodies did not assume a decided tendency to unite and 
combine, in proportion as they approach to their primitive or elementary state; the mass of elements 
would continually increase by these successive and uninterrupted decompositions; and we should insen¬ 
sibly return again to that chaos or confusion of principles, which is supposed to have been the original 
state of the globe. 
The necessity of this state of division, which is so proper to increase the force of affinity, has 
caused it to be admitted as an incontestable principle, that the difficulty of composition does not take 
place, unless one of the bodies be in the fluid state: “ corpora non agunt nisi sint fluidaT But it 
seems to me that extreme division might be substituted instead of dissolution; for both these operations 
tend only to attenuate bodies, without altering their nature. It is by virtue of this division, which is v 
equivalent to the dissolution, that the decomposition of muriate of soda is effected by trituration with 
minium, as well as the union of cold and dry alkali with antimony, and the disengagement of volatile 
alkali by the simple mixture of sal ammoniac with lime. 
Law III. The compound which results from the combination of two bodies, possesses properties 
totally different from those of its constituent principles. 
Some chemists have affirmed, that the properties of compounds were intermediate between those ol 
their constituent parts. But this term “ intermediate has no meaning m the present case, foi what 
intermediate qualities can exist between sour and sw 7 eet, or between w^atei and file? 
If we attend ever so little to the phenomena which are exhibited to us py bodies in their compo- 
