The Shaft Removed
1962 · Dismantling · Work 679 of 1,871
A single long precision shaft lifted clear of a dismantled analyser and laid across two wooden trestles, its bearing collars still on it spaced along its length, bright ground steel catching the light, the empty frame it came from behind with its open bearing housings, loose gears and bolts in a tray on the floor, in a university machine hall being cleared, one lamp lit over the shaft on its trestles, the hall beyond dark.
- What it was used for
- In the mechanical differential analyser every quantity was a rotation. Long shafts carried it across the frame from one integrator to the next, and differential gears added two rotations. To compute a different equation one relaid shafts and gears. Vannevar Bush's analyser at MIT was begun in 1927, according to the National Museum of American History, completed in 1930 and had six integrators. The Manchester machine, built in 1935 by the Metropolitan-Vickers Electrical Company for the university's physics department, is represented in the Science Museum by one part of it: a sixteen-foot central frame with four integrators, two input tables, an output table and a camera. During the Second World War the machine computed, among other things, for uranium enrichment.
- What was new
- There is nothing new about removing a shaft. What can be documented is what was lost in the process, and the museum records show it more precisely than any narrative. What was distinctive about these machines was that the shaft did not represent the quantity but was it; the relation between two quantities existed as a gear. That kind of construction cannot be preserved in part. The Manchester machine went to the National Physical Laboratory in 1948, to the College of Aeronautics at Cranfield in 1953, and returned to Manchester in 1965, where, according to the Science Museum Group, it was split up between departments; in 1973 the parts were reassembled into two different machines. Of the Bush analyser the Smithsonian holds two of the six integrators, together with gears and shafts as individual objects.
What the sources leave open: The sources consulted record no removal and no dismantling for the year 1962. The Science Museum Group dates the splitting up of the Manchester machine to 1965 and the rebuilding to 1973; the National Museum of American History gives no date of dismantling for the parts of the Bush analyser. Which machine the work refers to could not be settled, so both are named here and kept apart.