The photocopy, in that matter, was a disappointment; it added nothing about any particular recipient for the original text. However, from other materials in the same folder, Mike and I learned that the pencil version -- a copy rather than a source for the printed text -- had in fact been made for a gentleman named "Mr. Silver"; in an accompanying cover letter, Rae apologized that he had no copies of the pamphlet to spare, but had quite generously copied out the full text by hand. But who was this Mr. Silver?
Stephen William Silver, a London businessman, was known for much of his career for the concern he owned and managed, the India Gutta-Percha and Telegraph Works Company. In a manner similar to many other captains of industry, he was also a member and supporter of a number of learned societies, among them the Royal Geographical Society, of which he was elected a Fellow in 1856. Along with Dr. Rae, he served on its board, and they were likely acquainted from that moment. Silver had a lifelong interest in exploration, though his main focus seems to have been Africa -- but, apparently, he was interested in the Arctic as well. But how did this letter end up in Australia?
The answer lies in the person of a gentleman named Edward Petherick, who served as Silver's "bibliographical advisor." When Silver died in 1905, Petherick was concerned that the collection might be broken up, and seems to have written a friend in Adelaide about the possibility of the Public Library of New South Wales acquiring it; when that was politely declined, Petherick worked through friends and associates connected with the RGS, via which it was eventually acquired with the intent of passing it along to the RGSA. As the "York Gate Library" it was warmly received, eventually being housed in the State Library of South Australia, where it was opened with some fanfare in 1908.
And so, while this discovery doesn't tell us much new about Rae's open letter, it does say something about the man himself: that he would take the trouble, for a friend and colleague, to copy out his whole article again by hand, just for his solitary benefit.
[The author would like to acknowledge his reliance on Valmai Hankel's excellent article, "Not Silver but Gold: S.W. Silver and the York Gate Library" (2005), for details as to Silver's collection and its transfer to Australia.]