Copy letter from Robert William Frederick Harrison, to Dr Tempest Anderson, 17 Stonegate, York 'My dear Anderson, The Soirée Committee are quite willing for you to give a lantern demonstration in the Meeting Room illustrative of the recent eruption of Vesuvius. The date of the Soirée is Wednesday, June 20th. I enclose a schedule which you might fill up and return in the course of the next few days. I am, very truly yours, Robt [Robert] Harrison Assistant Secretary R.S. [Royal Society]'. 29 May 1906