48

PROOFS OF THE LAWS OF CHEMICAL APFINITY

together in a mortar, the two solids will act upon each other andform a fluid.

It is obvious therefore that in order to facilitate chemical affi-nity, the attraction of aggregation must be broken; the bodiesintended to be chemically united must not be presented to eachother in their mass of contact, but mechanically divided, or re-duced to the smallest moleculae possible.

Hence liquids combine with more facility than solids, or eventhan a solid and a liquid, and in like manner vapours combinewith rapidity and ease.

Law III..,.7%e agency of affinity of composition is influenced,ly temperature. Its action is either accelerated, retarded, pre-vented, or Tendered efficacious.

PROOFS OF LAW HI.

Experiment I.

If we expose phosphorus in an open vessel to the action of theatmosphere, a chemical union will take place between the phos-phorus and one of the constituent parts of the atmosphere,namely, the oxigen gas ; the phosphorus will gradually (but veryslowly) disappear, and become converted into a fluid calledphosphorous acid.

But if we heat the vessel containing the phosphorus, the latterwill take fire, and become converted into a yellowish white sub-stance, which in a short time is changed into an acid analogousto the former.

Experiment II.

If equal quantities of muriate of ammonia and carbonate ofmagnesia are mixt with six or eight parts of water, and sufferedto stand for some time exposed to the ordinary temperature ofthe atmosphere, a mutual decomposition of the two salts will