History of Chemistry in Ancient and Medieval India, Incorporating the History of Hindu Chemistry by Acharya Prafulla Chandra Ray c36.s7.9
History of Chemistry in Ancient and Medieval India, Incorporating the History of Hindu Chemistry by Acharya Prafulla Chandra Ray c36.s7.9
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c36.s7.9
The changes in colour, which the ruby and the sapphire undergo under the influence of heat, had evidently been carefully observed. This test is to be applied with extreme caution, as, in case the proper degree of temperature is exceeded, the stone may be materially injured.