Fig. 1 represents a neat case of small pneumatic apparatus, divided by partitions for the better arrangement of the articles. It contains a small air-pump, for exhausting and condensing, a water-pump and syphon, with a variety of articles for weighing the air, showing its pressure, elasticity, &c. A pamphlet and drawings accompany it to explain the design and uses of the whole. Price $37. In Figs. 2, 3 and 4, are shown the pump, and several experiments contained in the small case. Fig. 2 shows the method of exhausting a receiver with the small pump, both being ground to fit air-tight. The air is here admitted to the receiver by sliding the pump. Fig. 3 shows another method of connecting the pump, and raising a heavy weight by exhausting the air from a bowl with a bladder tied over it. To this a 50 lb. weight may be attached, and easily raised by the upward pressure of the atmosphere. The air is admitted by the long screw at the side. Fig. 4 represents the pump as used for condensing the air; in this experiment the lower valve is reversed, and the side screw near the top of the pump, is inserted in the bottom of the piston, to render it solid. At Fig. 5 is represented the Second Size Air-Pump, constructed to be portable, and yet sufficiently large to perform the usual experiments. It is operated with a simple lever, as being the most convenient method of applying the power of the hand. It has a syphon guage attached, which will indicate the degree of exhaustion in the receiver at any period of the operation. Price $25. The price of suitable Apparatus from $25 to $50. LARGE AIR-PUM P. Fig. 6 represents the Large Air-Pump; intended to show experiments at a considerable distance. This pump is simple in its construction, easy in its operation, and can be kept in order with very little trouble. It has a long barometer guage to indicate the degree of exhaustion. Price $50. Price of Apparatus, from $50 to $100. *1 Fig. 7. The small pump is generally sent as Fig. 8. STEAM ENGINES. Fig. 9. At Fig. 8, is represented a section model of the steamengine; by which the motions of the several parts, its internal structure, and the high and low pressure principles, can be easily explained. Prices $12 and $20. A working model of a steam-engine is shown at Fig. 9. They will be kept on hand and made to order at prices from $50 to $250. ts L Fig. 10. WATER PUMPS. Fig. 10 represents two water-pumps on a stand, the common lifting and the forcing pump. By the latter may be illustated the cause of a continuous stream from a Fire-Engine. Price $12. It will be observed in the catalogue of articles, that the pneumatic trough, vessels for compound blow-pipe, and several others, are of copper. All the apparatus liable to be exposed to moisture, or which are intended to hold water, we have generally made of copper or brass, on account of their greater durability when compared with tin. As the endeavor has been to make the apparatus as effective as possible, and many of the articles so simplethat any person under ordinary circumstances could repair them, changes have necessarily been made in several instances, both in the form and materials used. The apparatus for using a bladder as a hydrostatic bellows, is superior to the common form, inasmuch as the bladder being the only part liable to get out of order, the means of repairing it are generally at hand. The reflectors for showing the effects of heat, have the most suitable curve for concentrating the rays, the pattern having been made at considerable expense, by a scientific physician of this city. Those of brass are fitted into mahogany frames, which can be put together to form a box to preserve them from injury; a cannon, stand for a heated ball, air thermometers, &c. accompany them. The tin reflectors are smaller, polished, and mounted on common stands without apparatus. |