Plate, enlarged pores on a prism of tabasheer by [David Brewster] Plate containing a diagram of enlarged pores on a prism of tabasheer, likely drawn by Brewster. 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. 2 March 1819