Copy letter from Robert William Frederick Harrison, to [Messrs Harrison & Sons] Asks the Messrs to prepare electros of text figures one to eight inclusive, and of the four figures forming the plate illustrating the paper by Mr J E Petavel 'on the Pressure of Explosions' published in the 'Philosophical Transactions [of the Royal Society]' A 205, p357-398. They should be sent with the account to Herrn Rich Lehmann, Redaktion, Zeitschrift fur das gesamte Schiesz- und Sprengstoffwesen, Koniginstrasse 4, Munchen, Germany. 30 June 1906