It is unfortunate, considering that enthusiasm moves the world, that so few enthusiasts can be trusted to speak the truth.
Source, in full
Letter to Mary Gladstone Drew (17 May 1891), in Some Hawarden Letters, 1878–1913, Written to Mrs. Drew (Miss Mary Gladstone) Before and After Her Marriage, chosen and arranged by Lisle March-Phillipps and Bertram Christian (London: Nisbet & Co., 1917), p. 248.