Copy letter from Robert William Frederick Harrison, to Sir William Chandler Roberts-Austen Asks for the negatives of the photographs of the plate in Austen's paper on copper-gold alloys. Asks if he prefers the plate done in collotype of half-tone. Encloses two tracings [not enclosed] and queries if thee should be reproduced in fax-simile [facsimile] or reduced in size, and if he would prefer half tone blocks. 14 May 1900