rent colours. Thus the Calx of Silver tinges the Glass on which it is anneal'd with a lovely Yellow, or Gold colour, &c.
And that the parts of Metals are transparent, may be farther argued from the transparency of Leaf-gold, which held against the light, both to the naked eye, and the Microscope, exhibits a deep Green. And though I have never seen the other Metals laminated so thin, that I was able to perceive them transparent, yet, for Copper and Brass, if we had the same conveniency for laminating them, as we have for Gold, we might, perhaps, through such plates or leaves, find very differing degrees of Blue, or Green; for it seems very probable, that those Rays that rebound from them ting'd, with a deep Yellow, or pale Red, as from Copper, or with a pale Yellow, as from Brass, have past through them; for I cannot conceive how by reflection alone those Rays can receive a tincture, taking any Hypothesis extant.
So that we see there may a sufficient reason be drawn from these instances, why those colours which we are unable to dilute to the palest Yellow, or Blue, or Green, are not therefore to be concluded not to be a deeper degree of them; for supposing we had a great company of small Globular essence Bottles, or round Glass bubbles, about the bigness of a Walnut, fill'd each of them with a very deep mixture of Saffron, and that every one of them did appear of a deep Scarlet colour, and all of them together did exhibit at a distance, a deep dy'd Scarlet body. It does not follow, because after we have come nearer to this congeries, or mass, and divided it into its parts, and examining each of its parts severally or apart, we find them to have much the same colour with the whole mats; it does not, I say, therefore follow, that if we could break those Globules smaller, or any other ways come to see a smaller or thinner parcel of the ting'd liquor that fill'd those bubbles, that that ting'd liquor must always appear Red, or of a Scarlet hue, since if Experiment be made, the quite contrary will ensue; for it is capable of being diluted into the palest Yellow.
Now, that I might avoid all the Objections of this kind, by exhibiting an Experiment that might by ocular proof convince those whom other reasons would not prevail with, I provided me a Prismatical Glass, made hollow, just in the form of a Wedge, such as is represented in the tenth Figure of the sixth Scheme. The two parallelogram sides A B C D, A B E F, which met at a point, were made of the clearest Looking-glass plates well ground and polish'd that I could get; these were joyn'd with hard cement to the triangular sides, B C E, A D F, which were of Wood; the Parallelogram base B C E F, likewise was of Wood joyn'd on to the rest with hard cement, and the whole Prismatical Box was exactly stopt every where, but onely a little hole near the base was left, whereby the Vessel could be fill'd with any liquor, or emptied again at pleasure.
One of these Boxes (for I had two of them) I fill'd with a pretty deep tincture of Aloes, drawn onely with fair Water, and then stopt the hole with a piece of Wax, then, by holding this Wedge against the Light, and looking through it, it was obvious enough to see the tincture of the liquor near the edge of the Wedge where it was but very thin, to be a pale but
