Copy letter from Robert William Frederick Harrison, to William Bate Hardy, [Fellow of the Royal Society], 9 Park Terrace, Cambridge Referring to the suggested exhibit of the microscopical appearance of certain colloids, if Hardy's exhibit is only suitable for the upstairs room, he might carry on his trials until within a week of 9 May before deciding, but if he can make it a meeting room exhibit, it would be necessary to let them know this week if the exhibit can be promised. 24 April 1900