Fig. 12.
This model is worked with water-power only, and has no clockwork. The case you must make larger than in either of the former cases—24 in. high, 14 in. wide, and 14 in. deep; the height of the floor of the model from the bottom of the case 4 in., and the depth of the upper partition 4 in., the intermediate space closed by a glass door 16 in. by 14 in. The case must be made out of 1⁄2 in. stuff and well dovetailed together. In the right-hand bottom corner a drawer for the pennies with a slot in front. The back or one of the sides should have a door in it, to get at the machinery, should it at any time require attending to.
Fig. 13.
You must now make two zinc tanks, the top one air-tight, to occupy the whole of the upper space, the other also air-tight at first, to occupy the space left in the lower partition by the drawer. The top tank will be 13 in. by 13 in. by 31⁄2 in., and will have a small receiver, about 6 in. square by 1 in. deep, soldered to the bottom of it, and communication with it by a small hole, as shown in E, [Fig. 13], about a quarter of an inch in diameter, and having also a small pipe passing from it to the outer air through the large tank. This pipe is not shown in the figure, but it is soldered to the top and bottom of the tank and the ends filed off flush. The zinc for the bottom and sides of the tanks can be cut out of one piece, as shown in [Fig. 14]. The edges of the tops should be turned over, to add strength. The soldering must be made air-tight. The background of the picture is a false back inserted about 2 in. from the true one, behind which the pipes are placed connecting the vessels together, as shown in [Fig. 13], which is a back view.
Fig. 14.
These pipes must be carefully soldered in. A is the air-pipe to supply reservoir F when in use; B is the pumping-pipe, in the middle of which is fixed an india-rubber force-ball, to be procured at any india-rubber shop, in which is a small pin-valve, to prevent the water flowing back. This pipe extends from the bottom of tank G to the top of tank F, leaving a space of about 1⁄8 in. between the ends of the pipes and the metal of the tanks. C is a small pipe by which the water from the basin of the fountain is run into G. E is the receiver into which water from F runs, and from which two pipes lead, one to the wheel of the mill, and the other to the fountain. K is a regulating tap, to govern the supply of air and regulate the amount of water passed into E. D is the stopcock connected with the starting lever, which is about 6 in. long and soldered to the handle of the tap. This tap must work easily, and yet be air-tight.
The lever must be counterweighted, to close the tap when the penny has fallen off the scoop at the end of the lever. H is a small pipe fixed in the top of the tank G to allow the air to pass out when the water is running into it through C. The basin of the fountain should be made of zinc, and fastened to the tube C, and the jet is formed of the end of a blow-pipe connected to the tube from E. The rockery you must form of cinders and paint them to a suitable colour. The mill-wheel should be made of zinc and painted, and the water from it conducted to the basin of the fountain. The other pipe from E you must conduct to a position suitable to set the wheel in motion.