Letter from Percival Lowell, Lowell Observatory, Flagstaff, 53 State Street, Boston, Massachusetts, to Robert [William Frederick] Harrison, Assistant Secretary of the Royal Society 'Dear Sir :- I have to-day wired you as follows: "Let the engraver work from the Mars photographs you have", as by mistake the positives sent me were enlarged too much, and I think also that the engraver will do as good work from the prints now in your possession as from negatives or positives of them. Believe me, Faithfully yours; Percival Lowell'. 2 November 1905