W1516 TO DR. CALVIN BROOKS MCQUESTEN from Samuel A. Duncan
Jan 19 1884
I have a report on the car coupler1 examination, & will show it to you when you can find it convenient to call.
S.A. Duncan Esq.
1 This refers to the train car couplers that William Dunn had patented and for which Isaac had invested much money to support Dunn in his efforts to sell them. However, Dunn was unsuccessful when it came to selling the patents for a good profit and he eventually agreed to repay Isaac or turn over the patents and related materials as compensation (W2609 and links). For more on Dunn, see W2554a.