Thirdly, That most of the simple ideas that make up our complex ideas of substances, when truly considered, are only powers, however we are apt to take them for positive qualities; v.g. the greatest part of the ideas that make our complex idea of gold are yellowness, great weight, ductility, fusibility, and solubility in aqua regia, &c., all united together in an unknown substratum:  all which ideas are nothing else but so many relations to other substances; and are not really in the gold, considered barely in itself, though they depend on those real and primary qualities of its internal constitution, whereby it has a fitness differently to operate, and be operated on by several other substances.

CHAPTER XXIV.

Of collective ideas of substances.

1.  A collective idea is one Idea.

Besides these complex ideas of several single substances, as of man, horse, gold, violet, apple, &c., the mind hath also complex collective ideas of substances; which I so call, because such ideas are made up of many particular substances considered together, as united into one idea, and which so joined; are looked on as one; v. g. the idea of such a collection of men as make an army, though consisting of a great number of distinct substances, is as much one idea as the idea of a man:  and the great collective idea of all bodies whatsoever, signified by the name world, is as much one idea as the idea of any the least particle of matter in it; it sufficing to the unity of any idea, that it be considered as one representation or picture, though made up of ever so many particulars.

2.  Made by the Power of composing in the Mind.

These collective ideas of substances the mind makes, by its power of composition, and uniting severally either simple or complex ideas into one, as it does, by the same faculty, make the complex ideas of particular substances, consisting of an aggregate of divers simple ideas, united in one substance.  And as the mind, by putting together the repeated ideas of unity, makes the collective mode, or complex idea, of any number, as a score, or a gross, &c.,—­so, by putting together several particular substances, it makes collective ideas of substances, as a troop, an army, a swarm, a city, a fleet; each of which every one finds that he represents to his own mind by one idea, in one view; and so under that notion considers those several things as perfectly one, as one ship, or one atom.  Nor is it harder to conceive how an army of ten thousand men should make one idea than how a man should make one idea it being as easy to the mind to unite into one the idea of a great number of men, and consider it as one as it is to unite into one particular all the distinct ideas that make up the composition of a man, and consider them all together as one.