The complete score is available as a PDF on my website, but it'll take a long time to load!
The "handler" was to influence the Bride's decisions by responding to changes in a sort of gravitational field — the details are unclear, and in any case the handler was ultimately left out of the painting. Duchamp's note is accompanied by a sketch of a six-pointed star-shape surrounding a spheroid body; the six points represent points from which threads would stretch toward the central body, defining its location and shape by their tension.
Six systems of music, each lasting about a minute, were conceived as both linear and textural analogues of these threads. The unsynchronized repetitions and reinforcements in the music was meant to represent the variations and displacements of physical bodies caused by gravitational disturbances.
Much of this was suggested by the curious rhythmic disturbances which frequently characterize organists — or, rather, their performances. The result is a rather different kind of organ writing, a sort of comporomise between standard notation and a kind of tablature; the hope is to ensure an idiomatic organ character by harnessing the little clumsinesses of the instrument.
The organist must be the central body who determines but also is subject to these disturbances — by realizing the music as accurately as possible (with respect to dynamics and pitch) while altering "rhythm" by responding to the difficulty of fingering (and footing), to the acoustical circumstances of the room, to the registration possibilities (themselves determined by octave location and dynamic), etc., etc.
Handler of Gravity was premiered in the Chapel on the campus of Mills College on March 13, 1971. I think the organist's name was Ted Ashford; I can't find any of my concert programs at the moment. (When I looked for them just now, though, I did find my good pair of glasses, missing a number of months.) I wish I had a recording of the concert: it lasted an hour or so, and involved simultaneous performances of Handler of Gravity (with someone — David Smith, I see, now I look at the score, and, yes, it was Ashford — playing the optional chimes and glockenspiel), three graphic pieces for string quartet; and occasional overlays of Bachelor Apparatus, for four pairs of trumpets and trombones (they were stationed outside the chapel).
There have been three quite different adaptations of the original score, each about eight minutes in duration:
Five Pieces after Handler of Gravity, for solo piano (premiere: Nathan Schwartz; Jan. 17 1976, Oakland Museum). Each of these pieces was provisionally dedicated to one or another of the five music critics on the three major daily newspapers in the San Francisco area at the time, since Duchamp sometimes referred to his Handler as a "Juggler of Gravity."
score: FP she03, 12 pp., available from Frog Peak Music
Tender of Gravity, for nine instruments (fl-pic, o-eh, cl-bass cl, bn, harmonium, vn, vla, vc, cb) (premiere: Irene Pruzan, Lenore Sleeter, Tom Rose, Cyrle Perry, Beth Anderson, Nathan Rubin, Ron Erickson, Teressa Adams, Jedediah Denman; 9 May 1974; 1750 Arch Street, Berkeley)
score: FP she04, 14 pp., available from Frog Peak Music
Ballet: Handler of Gravity, for full orchestra (3-2(eh)-2-2(cbn)/4-2-3-1/pno/hrp/1perc/timp/strings) (premiere: Shere, Contra Costa Symphony, Kensington, Calif., 28 Oct. 1976), as part of a compilation provisionally called Music for Orchestra). This version also stands at the end of the second act of the full-length opera The Bride Stripped Bare by Her Bachelors, Even.
score: Ear Press, 14 pp.,available from Frog Peak Music