Dennis Hart Mahan

- 16 September 1871

At the end of his plebe year Mahan stood first in mathematics and second in French, being first in order of merit in his class of 73 [Greiss, p. 103]. Having mastered algebra and some geometry his first year, he continued in the second with geometry, analytical trigonometry, spherical projections, descriptive geometry, and fluxions [Greiss 104]. His studies were interrupted in November 1820 when he was appointed Acting Assistant Professor of Mathematics. This had several privileges, including

Teaching plebe mathematics each morning from 8:00 to 11:00 caused a severe burden on Mahan for he could not attend his own mathematics class except on those occasions when Mathematics Professor David B. Douglass was giving a lecture to the plebes.

 

His son, Frederick August Mahan (Cullum #2166) taught at USMA, 1869-1872.

Publications:

"On practical geometrical methods of loci," The Mathematical Monthly (of Runkel), vol. 1 (1859), pp. 217-219. Rickey has a copy of this volume. 

In this article, Mahan mentions "my old friend and professor years ago, General Poncelet, Member of the French Institute." I presume that this resulted from his study in France. The article ends with the words: "To instructors I will permit myself to add, that, as an introduction to practical applications of geometrical constructions, exercises of this character at the black-board, with a scale, dividers, and a triangle, will be found of the greatest service to the young engineer." This is interesting for it tells something about what was actually done at the "black-board." I have not read this article carefully, but should do so. 

Mahan says someone should translate Poncelet's Memoirs on the Stability of Retaining Walls and Arches. The USMA library has

Poncelet, M. (Jean Victor, 1788-1867), Sustaining walls : geometrical constructions to determine their thickness under various circumstances / derived chiefly from a memoir of M. Poncelet ; with modifications and extensions by Capt. D.P. Woodbury under the direction of Bt. Brig. Gen. J.G. Totten. Washington : Taylor and Maury, 1854, 2nd ed.

but this not be the correct book. Surely, Mahan would have known of this. 

Industrial Drawing, 1868. The preface indicates that he is following in the footsteps of Dupin, Bergery, and Poincelet. One USMA copy contains a great student sketch indicating that reading this is like pulling teeth [Spec. T353 .M21 1868; See Rickey's Library Notes, p. 46].

Genealogy:

His son, Frederick August Mahan (#2166) is a graduate.

Obituaries:

Dictionary of American Biography.

Assembly April 1872.

Cullum #361: [Shield=Ancestor] B-NY: A-VA: CE: Asst Prof Math&Engr USMA 24-26 2LT: French Mil School Metz 26-30: Actg Prof Engrg USMA 30-32 & Prof 32-71; Distinguished educator and writer: Honored by many universities: Mem many scientific societies: D-Near Stony Point NY (drowned) 16Sep71 a-69: A world renowned scholar who taught the Science of War to many world famous graduates: DAB: Ob-AR 72 [From 1990 Register of Graduates]

 

References:

Thomas Everett Greiss, Dennis Hart Mahan: West Point Professor and Advocate of Military Professionalism, 1830-1871, Ph.D. dissertation, Duke University, 1968. Dissertation Abstracts 69-16,754.