Hand (unit) inches for the handsbreadth; Mortimer gives the same, three inches for the Hand's-breadth, and four for the "Handful, or simply, Hand", but adds "The hand among horse-dealers, &c. is four-fingers' breadth, being the fist clenched, whereby the height of a horse is measured", thus equating "hand" with both the palm and the fist. Similarly, Wright's 1831 translation of Buffon mentions "A hand breadth (palmus), the breadth of the four fingers of the hand, or three inches", but the "Encyclopædia Perthensis" of 1816 gives under Palm (4): "A hand, or measure of lengths comprising three inches". Today the hand is used
Hand-Held Maneuvering Unit use his HHMU on Gemini 11, because his EVA had to be cut short when he became fatigued. Hand-Held Maneuvering Unit The Hand-Held Maneuvering Unit (HHMU), also known as the maneuvering gun, or informally as "the zip gun", was used by astronaut Ed White in the first American "spacewalk" (extra-vehicular activity, EVA), on Gemini 4, June 3, 1965. Different models of HHMU were present on Gemini 4, 8, 10, and 11, but were only used on Gemini 4 and 10. It was also used aboard Skylab. Astronauts described the gun as easier to use than other methods of maneuvering during