For the determination of the character of the watermark we are indebted to Mr. John N. Luff, whose thoroughness and acumen when delving into a philatelic problem are proverbial. The result of his study was published in 1895[99] and we take the following extracts from his interesting paper:--
[99] =American Journal of Philately=, VIII: 77.
Most philatelic writers, when treating of the Canadian issue of 1868-75, give small space to the series watermarked with large letters. Most of them make a few speculative remarks as to the probable watermark and then drop the subject. So far as I am aware, no one has taken the trouble to ascertain what the watermark actually is. The London Society in the _North American Colonies of Great Britain_ says: "Some of the stamps on wove paper have been catalogued with a watermark, consisting of various letters. It is probable that these letters are portions of the name of the papermaker, which most likely exists in the margin of the sheets." Other writers are equally superficial. The _Catalogue for Advanced Collectors_ says: "Although we catalogue as varieties the stamps on watermarked paper, it is very possible that these form a separate issue. It may have happened that the printers, having-run short of the regular paper, replaced it by some similar paper that they had in stock, bearing this watermark"....
In the _Stamps of British North America_, by Messrs. C. B. Corwin and Donald A. King (_Metropolitan Philatelist_, June 1891), this watermark is given more attention. The possibility that it is the words "Canada Postage" or "Canada Post Office Department" is discussed and rejected, because the authors have found certain letters and pairs of letters which do not occur in these words.
It has seemed to me that it would be of interest, probably of value, to know exactly what this watermark is. I have therefore given the matter considerable study, and now have the pleasure of presenting the result to your readers. The extensive stock of the Scott Stamp & Coin Co., being placed at my disposal, together with a quantity of stamps from private sources ... I believe I have correctly reconstructed the watermark.
As the broadest letter measures only 12 mm., and the stamps are about 23mm. from center to center of perforations, there are usually parts of two or three letters on each stamp. I have found a large number of single letters, pairs, portions of three letters, and in one instance, a pair and parts of two letters. Of many combinations I have found several examples. I have also found quite a number of stamps showing parts of two rows of letters, one above the other.