never.  And if this be not allowed to be so, I do not know how they can be excused from murder who kill monstrous births, (as we call them,) because of an unordinary shape, without knowing whether they have a rational soul or no; which can be no more discerned in a well-formed than ill-shaped infant, as soon as born.  And who is it has informed us that a rational soul can inhabit no tenement, unless it has just such a sort of frontispiece; or can join itself to, and inform no sort of body, but one that is just of such an outward structure?

21.  And can hardly be made known otherwise.

Now these leading qualities are best made known by showing, and can hardly be made known otherwise.  For the shape of a horse or cassowary will be but rudely and imperfectly imprinted on the mind by words; the sight of the animals doth it a thousand times better.  And the idea of the particular colour of gold is not to be got by any description of it, but only by the frequent exercise of the eyes about as is evident in those who are used to this metal, who frequently distinguish true from counterfeit, pure from adulterate, by the sight, where others (who have as good eyes, but yet by use have not got the precise nice idea of that peculiar yellow) shall not perceive any difference.  The like may be said of those other simple ideas, peculiar in their kind to any substance; for which precise ideas there are no peculiar names.  The particular ringing sound there is in gold, distinct from the sound of other bodies, has no particular name annexed to it, no more than the particular yellow that belongs to that metal.

22.  The Ideas of the Powers of Substances are best known by Definition.

But because many of the simple ideas that make up our specific ideas of substances are powers which lie not obvious to our senses in the things as they ordinarily appear; therefore, in the signification of our names of substances, some part of the signification will be better made known by enumerating those simple ideas, than by showing the substance itself.  For, he that to the yellow shining colour of gold, got by sight, shall, from my enumerating them, have the ideas of great ductility, fusibility, fixedness, and solubility, in aqua regia, will have a perfecter idea of gold than he can have by seeing a piece of gold, and thereby imprinting in his mind only its obvious qualities.  But if the formal constitution of this shining, heavy, ductile thing, (from whence all these its properties flow,) lay open to our senses, as the formal constitution or essence of a triangle does, the signification of the word gold might as easily be ascertained as that of triangle.

23.  A Reflection on the Knowledge of corporeal things possessed by Spirits separate from bodies.