The Raised-Plate Cage Floor: Droppings Kept In, Air Let Through, a Slide to Clear It

"The upwardly and inwardly directed portion 13 is provided with a plurality of relatively large apertures 15 to decrease the weight and to increase the circulation of air, as hereafter explained." "The plate is thus spaced away from the bottom 12 a distance equal to the lengths of the posts 20, and the plate extends at its margin beneath the sides of the cage, and is spaced from the upturned margin 13 of the bottom." "With a device thus constructed the air circulates freely beneath the plate 21 and thus materially improves the circulation and prevents the accumulation of dead or foul air."

**Bottom.** Measure the bought cage's bottom rim. From aluminium sheet cut a piece 16 cm longer and wider, fold 6 cm up on each side into a tray, snipping the corners, and bend the top 2 cm of each wall inward, so the tray's floor is 2 cm larger than the cage all round and its lips meet the cage's wires. Lay out a row of 20 mm holes along each wall, centred 3 cm up, below the lips, and cut them with the hole saw; file their edges smooth. **Plate.** Cut a plate of aluminium sheet 1 cm larger all round than the cage's bottom, so it reaches under the cage's sides but stays 1 cm clear of the walls. Bolt four hex bolts through the tray's floor, with a nut run down each to 1.5 cm, and rest the plate on the nuts, below the holes; turn up its corners 5 mm as stops. **Slide.** Cut a 6 × 1.5 cm opening in one wall at floor level, between two holes, so it opens under the plate. Bend two strips of sheet into channels and fix them with pop rivets either side of it, and slip in a small plate of sheet as the closure. **Test.** Stand the cage on the plate, with its wires against the tray's lips. Scatter a cupful of lentils and a spoon of flour on the plate and tap the cage twenty times. Count the lentils that leave the tray, open the slide, and sweep out what fell under the plate.

**John E. Compton** of Red Lodge, Carbon County, Montana, filed US 963,995 on 23 June 1909; it was patented 12 July 1910. His cage is round, of upright wires 10 with a band 11; the bottom 12–13 is preferably spun from sheet metal, brass or another metal, plated or ornamented, its edge rolled at 14 round a binding wire. Sliding catches 16 through keepers 17 bear on stop plates 18 to hold the cage to the bottom; the plate 21 rests on posts 20 with stops 22; the opening 23 has a sliding closure 24. Bottom and plate come apart for cleaning. His claim covers the bottom with a perforated upward margin and a smaller plate supported above the bottom and below the perforations. **Honest limits.** A folded square tray of aluminium stands in for his spun brass bottom, and nuts on bolts for his posts. The notebook treats the margin as flat sheet; its sizes are examples. Your counts are the result.