Paper, 'On the optical and physical properties of tabasheer' by David Brewster in a letter to the Right Hon Sir Joseph Banks 24 manuscript pages include one plate showing a prism of tabasheer. Subject: Mineralogy Published in Philosophical Transactions as 'On the optical and physical properties of tabasheer. By David Brewster, LL. D. F. R. S. Lond. and Edin. In a letter to the Right Hon. Sir Joseph Banks, Bart. G. C. B. P. R. S. &c. &c. &c'. Written by Brewster in Edinburgh. Read 6 May 1819. Abstract published in Abstracts of the Papers Printed in the Philosophical Transactions of the Royal Society of London [later Proceedings of the Royal Society of London], Volume 2, 1833. 2 March 1819