Tanks for the link, seemingly a lot of stuff is hidden in the vaults of Harward, like
Consists of 39 of Rumford's drawings in pen and watercolor of his inventions; 24 drawings for him by Georg von Reichenbach, a Bavarian army engineer; maps; and engravings including some of the English Garden in Munich designed by Rumford and of plans for a military post near Dublin. Rumford's drawings are of a hackney carriage with wooden springs, coffeepots, portable stoves, fireplaces, chimneys, and mantelpieces. Reichenbach's drawings are of flint-lock muskets and other small firearms, field cannons, and military uniforms. Also contains drawings and engravings of miscellaneous scientific and architectural apparatus, by various hands, possibly not connected with Rumford.
Citation: Benjamin Thompson Rumford Drawings, 1795-1806 (MS Am 1550-1550.1). Houghton Library, Harvard University.
Notes: Material is in French.
References: For reproductions and description see Brown, Sanborn C., "Scientific Drawings of Count Rumford at Harvard," Harvard Library Bulletin, IX, 1955, p. 350-364, plates I-XVI.
Author: Reichenbach, Georg von, 1771-1826.
Subject: Rumford, Benjamin, -- Graf von, -- 1753-1814.
Gardens, English -- Germany -- Munich -- 19th century.
Inventions -- Germany -- 19th century.
Military uniforms -- Bavaria.
Keyword: Occupation: Engineers.
Form / Genre: Architectural drawings 19th century.
Drawings Germany 19th century.
Drawings 19th century.
Engravings 19th century.
Creation Date: 1795
HOLLIS Number: 000602531
Source: HVD ALEPH
Seemingly not as accessible as from our dear friends of ASK Brown collection