To my surprise, in the course of compiling the bibliographical information for an upcoming number of The Historians Guide to Conjuring (Redux) (HGCR) on the various English-language editions of Robert-Houdins autobiography, I have found that the so-called Alta edition and other editions published by Porter & Coates and Henry T. Coates (successor to Porter & Coates) have a large variety of binding styles and cloth colors. I have at least 14 variants and know there are more out there! Thousands of these books must have been produced, as they are by far the most common of the older editions of R-Hs book.
I am writing to enlist the aid of you collectors who might have a copy of the Porter & Coates and/or Henry T. Coates edition, and would be interested in hearing what you have: the name of the publisher, the color of the cloth, whether it says Alta on the cover or spine, etc. Because Im a nut and dont have enough copies of this book, Id be happy to purchase any copy I dont have. In fact, Ill make you this offer: if I end up purchasing your copy, Ill give you a free copy of the next installment of HGCR (the first number is almost sold out and sold for $47.50 plus shipping). Even if you dont want to sell, Id like to hear from you (buying the book is a distant second to the information).
P.S. I'd also be interested in knowing if you have a R-H autobiography published by H. B Graves. This edition used the same binding as one used by Porter & Coates, with only the name of the publisher being changed.