CLYDE SEA AEEA. 665 



guides for the slip cylinder. On the upper part of the top-plate there is a slight hollow 

 which causes a disc of soft indiarubber, 4 inches in diameter, fixed by a nut screwed down 

 from above, to assume a saucer-like shape. Above the top-plate the central tube is 

 surrounded by an outer tube of brass, 1J inches in diameter, the lower end of which is 

 screwed firmly into the top-plate, and the upper end is brazed to a flange on the top of 

 the central tube. About 4 inches above the top-plate two windows, 1 inch long and f inch 

 wide, are cut opposite each other in the outer tube, and through these project two brass 

 catches cut square below but tapered in a convex curve above, so that the points remain 

 just within the central tube while the bases project about one-eighth of an inch. These 

 catches are brazed to long brass springs firmly riveted to the central tube some distance 

 below the windows. The upper extremity of the outer tube is surrounded by a counter- 

 sunk brass ring from which three equidistant detaching springs of hammered brass, about 

 3 inches long and one third of an inch wide, turned sharply out at the end, radiate down- 

 ward and outward like an inverted shuttlecock. This completes the fixed part of the 

 apparatus. A slip-cylinder about a foot long, made of brass tube 4 inches in diameter, 

 terminates below in an edge roughened by a narrow groove being cut in the centre so as 

 to give it a A -shaped section and enable it to indent the indiarubber ring of the base- 

 plate, when shut down, with a very firm grip. The upper edge of the cylinder has an 

 annular knife-edge projecting inward, and so adjusted that it presses on the indiarubber 

 saucer of the top-plate when the lower edge rests on the ring of the base-plate. A brass 

 dome of three limbs, weighted with lead inside, springs from the upper end of the slip 

 cylinder and carries a strong ring sliding easily on the outer tube. The upper end of 

 this ring is prolonged into an annular gallery in the side of which, internally, a deep 

 groove is cut ; and on the floor of the gallery there are two notches opposite each other, 

 about f-inch wide, cut in from the tube. A third part of the apparatus is a short 

 detaching tube which slides easily over the shuttlecock springs at the top of the instru- 

 ment, drawing them in close against the side of the tube. An indiarubber buffer and 

 broad perforated brass disc above prevent this tube from being driven down far enough 

 to strike the projecting tips of the springs. The slip cylinder is slipped on the outer 

 tube before the shuttlecock-spring is placed in position. Then, by pressing the detaching 

 tube over the shuttlecock, the arms are brought in, and, the gallery of the cylinder being 

 brought to its place, the detaching tube is raised, and the shuttlecock-spring, expanding 

 into the groove in the side of the gallery, suspends the cylinder, holding it very firmly. 

 To close the water-bottle the detaching tube is pressed down, thus withdrawing the 

 shuttlecock retaining-spring and the cylinder slips by its own weight along the guides. 

 When the lower edge of the ring reaches the windows in the outer tube the locking 

 springs are pushed in, and when the edges of the cylinder strike and indent the two 

 indiarubber surfaces, the locking springs shoot out above the floor of the gallery on which 

 they press, locking the slip cylinder firmly to the body of the apparatus and securely 

 retaining the water it contains. Care must be ta,ken in adjusting the slip cylinder that 

 the notches in the gallery are not opposite the windows of the outer tube. To re-set the 



VOL. XXXVI. PAKT III. (NO. 23). 5 H 



