Opticks: Or a Treatise of the Reflections, Refractions, Inflections & Colours of Light

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1730 Excerpt: ...can be made of them,) as soon as I had blown any of them them I cover'd it with a clear Glass, and by, that means its Colours emerged in a very regular order, like so many concentrick Rings encompassing the top of the Bubble. And as the Bub ble grew thinner by the continual subsiding of the Water, these Rings dilated flowly and overspread the whole Bubble, descending in order to the bottom of it, where they vanilh'd successively. In the mean while, after all the Colours were emerged at the top, there grew in thecenter of the Rings a small round black Spot, like that in the first observation, which continually dilated it self till it became sometimes more than £ or of an Inch in breadth before the Bubble broke. At first I thought there had been no Light reflected from.the Water in that place, but observing it more curiously, I saw within it several smaller round Spots, which appeared much blacker and darker than the rest, whereby I knew that there was some Reflexion at the other places which were not so dark as those Spots. And by farther Tryal I found that I could fee the Images, of some things (as of a Candle or the Sun) very faintly reflected, not only from the great black Spot, but also from the little darker Spots which were within it. Besides the aforesaid colour'd Rings there would often appear small Spots of Colours, ascending and descending up and down the sides of the Bubble, by reason of some Inequalities in the subsiding of the Water. And sometimes small black Spots generated at the fides would ascend ascend up to the larger black Spot at the top of the Bubble, and unite with it, Obs. 18. Because the Colours of these Bubbles were more extended and lively than theft of the Air thinn'd between two Glasses, and so more easy to be distinguish'd,...