Encyclopaedia Britannica Or A Dictionary Of Arts Sciences And Miscellaneous Literature Vol 15 Of 18 PDF Download

Excerpt from Encyclopaedia Britannica, or a Dictionary of Arts, Sciences, and Miscellaneous Literature, Vol. 6 of 18: Constructed on a Plan, by Which the Different Sciences and Arts Are Digested Into the Form of Distinct Treatises or Systems Diamond pation ofdiamonds, or ocoafioned any degree of fufion. By this heat rubies were foftened, and loll fome of their colour, but preferved their form and weight. By addition of a third lens, ' a further degree of fufion was given to rubies. Even then rubies could not be made to unite with glafs. By having been expofed to this heat, the furface of the rubies which had lingered fu fion, loll: much of their original hardnefs, 'an'd were nearly as foft as cryital. But their internal parts, which had not been fufed, retained their hardnefs. E meralda by this heat were rendered white, or of various colours, and foon afterwards were ful'ed. They were found to have loft part of their weight, and to be ren dered lefs hard and brittle. Experiments were alfo made by order of the empe ror Francis I. On precious ftones from which we find, that diamonds were entirely diilipated by having been expofed 1n crucibles to a violent fire of a furnace du ring 24 hours while rubies by the fame heat were not altered 1n weight, colour, or polilh. By expofing dia monds during two hours only at a time, (the following alterations roduced on them by fire were obferved. Firfi, they lhfl their polifh then they were fplit into thin plates and, lafily, totally diffipated. By the fame wfire, emeralds were fufed. See Magq/z'n dc Ham bourg, tom. Xviii. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.