In simply asking this question, “How does a non-carpenter (Long) come to the specific carpenterly conclusions he had?” I found myself set upon a path in search of, answers if possible, and at least real clues as to how he might have garnered this information.
So logically this begins with looking at the first patent of 1830, and the work and probable constructions which led to the filing of his letters patent.
His biographers tend to skim right over his multiple bridge patents, preferring to emphasize his military expeditions of the west, and seeming to view the the bridge trusses as but a small aspect of his involvement in Railroads. Work which began in surveys and planning railbeds as a member of the Army’s Topographical Engineers, but seems to have for the Bvt. Col., often morphed into private sector opportunity, (this an accepted norm of the day) and his RR machinery patents, seem to outnumber his five bridge patents. (some mere improvements, but three are distinctly differing trusses) A leave of absence was even brought on by a brief partnership in a locomotive mfg. co.
Long’s Truss seems to have been developed during a time he was working for the Baltimore & Ohio RR, several examples being built. Though by 1836, perhaps to save the running foot price for use of a patent truss, they were building bridges of the truss type pictured below, designed by their in house engineer Benjamin Henry Latrobe Jr.
Biographies shedding little light on his bridgework, forced a search into source materials. And thankfully, private sector activity encourages shameless self promotion. Surprisingly, Stephen’s time was rife with this, and there are numerous pamphlets and recurring releases of his “Description” and also press release type periodical mentions. The man was actually taking time to “post” such releases.
And sifting through all this chaff, looking for that kernel of wheat, I am about thunderstruck to find a similar shameless self promotion type inclusion, about a bridge patent no less, from the good Colonel’s own brother – A younger brother who stepped into Stephen’s very long shadow. (Several brothers went onto higher learning, Dartmouth included, but George Washington was the only one to attend West Point and follow on into the Topographical Engineers)
This does provide a window on their world, (and provides a first hand account that the common story of men stepping up onto models at meetings was something that did happen) and suggests not only were these brothers in regular communication despite their distance, but that Stephen’s bridge work was both seen already with some importance, and that it was also well fleshed out by January 1st 1831.
No such patent seems to have been filed, do wish to find the drawings, they must be out there somewhere. GW’s talk of iron or combination examples is cutting edge, almost ahead of his time kind’a stuff
Sibling rivalry, if ever a factor, would seem to have been put aside by the 1850’s, as both brothers like all their surviving siblings, (a sister and her family included) retired to Alton Illinois. A family reunited