W1522 TO DR. CALVIN BROOKS MCQUESTEN from William Dunn
Oct 25 1884 Saturday 3.30 P.M
To: Dr. McQuesten 784 Lexington Ave., [New York] City
Almost immediately after you left the fact occurred to me. That the Canadian Patent (of Couplers) and the U.S. Patent were not similar.1 In fact, the most important claims in the U.S. Pat. are not embodied in the Canadian Patent.
I know that I had discussed the question several years ago, and had become satisfied of the validity. But in conversation with you today, could not at the moment recall my reasons for the conviction. Either tonight or Monday morning, I will mail you the particulars although much of it will have to be drawn from Memory as I have no data here to write now.
P.S. As you have the U.S. Patent here. To save time I will drop a Postal to your Brother tonight asking him to send to you the Canadian Patent. So that the subject can be intelligently understood without relying altogether on my memory which might be faulty.
1 Dr. Calvin Brooks McQuesten and his brother Isaac were involved with Mr. Dunn in business concerning train car couplers. Isaac had funded a significant portion of Dunn's efforts to sell his machine patents, but never saw a return on his investment and eventually considered suing. See W2554a for more details.