Autograph letter signed from Sylvain van de Weyer to Mary Horner Lyell, no place or date: "We fully intended having the pleasure of waiting upon you on the 21st; but we were prevented from doing so by the arrival of some Belgians, who remained with us till too late an hour to make our appearance. We very much regret the untoward event [...]". To Sir Charles Lyell: "My Dear Sir[,] a speech is, at all times, a formidable thing, but will appear less so, after a few moments’ conversation with you on the subject. I shall then accept with great pleasure your invitation for the 16th [...]".