Published online by Cambridge University Press: 01 May 2009
From time to time I have accumulated a large number of results obtained in identifying precious stones by means of their specific gravity. From these results I have selected about 70, which will be found arranged below. The observations have been made with care, and, where no temperature is given, at 15° 5 C.; an asterisk denotes those determinations in which a very accurate assay balance by Oertling was used, and in which the specimens were immersed in alcohol, not in water. In these latter determinations any error would be confined to the third place of decimals.
page 320 note 1 Kick, (Pol. Notizbl. xxix. 105Google Scholar; Pol. Jour. ccxii. 40) employs for the atching of artificial iron and steel a mixture of one part of hydrochloric acid and one part of water, to which a little antimony chloride has been added. Surfaces etched with this liquid are less liable to rust. Kick states that some irons and steels are quite passive, but that this property may be destroyed by raising them to a red heat.Google Scholar
page 324 note 1 The substance of the following communication was laid before the Geological Society 24th June, 3874, by permission of the Director-General of the Geological Surveys. It is reproduced in its present form in order that the accompanying theories may evoke some criticism, which they could not receive when the original article, together with 26 others, was read in brief abstract at the last meeting of the Session.