Cajori is referring, I think, to Harry Clinton Gossard (1884-?)
I don't have much information at hand, but one might contact
archivists both at the Johns Hopkins University and University
of Oklahoma.
It might be worth mentioning that Gossard's Ph.D. dissertation,
entitled "On a Special Elliptic Ruled Surface of the Ninth Order",
was addressed at Johns Hopkins University in 1914, and published
in the _American Journal of Mathematics_ vol XXXVIII, no 4,
October 1916.
With best regards from Montevideo,
Julio Gonzalez Cabillon
PS: A courtesy copy of this message is being sent to Jennifer Rallo
and Jim Stimpert, archivists at Johns Hopkins University. Likewise,
I included OU Public Affairs' address in the recipient list.
At 01:16 AM 13/06/1999 +0100, John Fauvel <J.G.Fauvel@open.ac.uk> wrote:
> Does anyone know anything about H. C. Gossard? As in Cajori's History
> of Mathematics p.298:
>
> "H.C.Gossard of the University of Oklahoma showed in 1916 that the
> three Euler lines of the triangle formed by the Euler line and the
> sides taken in twos, of a given triangle, form a triangle triply
> perspective with the given triangle and having the same Euler line."
>
> Many thanks,
> John Fauvel
> Open University, UK