WHEN I suggested you as the "Sapeur of modern progress," my dear Henry, I thought to convey delicately my appreciation, wrapped in graceful compliment.
When I am made to say that you are the "Sapem" of civilisation - whatever that may mean - I would seem to insinuate an impertinence clothed in classic error.
I trust that, if you forgive me, you will never pardon the printer. -
1. 9 September 1886
Date of first publication, in Truth, 9 September 1886.
This transcription is based on the letter as republished in Whistler, James McNeill, The Gentle Art of Making Enemies, 2nd ed., London and New York, 1892, p. 173, under the heading 'The Inevitable'.
The word 'sapem' printed in Truth was, as JW says, meaningless.