AIR PUMPS AND APPARATUS, 



IMPROVED LEVER AIR PUMP. 



THIS elegant instrument (Fig. 17 7, opposite page), mounted 

 on a strong and highly polished frame, or table, made of 

 mahogany or rosewood, consists of two rectangular boards 

 two inches thick, twenty-seven inches long, and seventeen 

 inches wide ; supported twenty-four inches apart by four 

 hollow pillars, and connected together by iron rods secured 

 in the legs beneath, and having brass knobs at the top of 

 the frame ; thus binding the whole strongly together, and 

 affording facilities for separating the parts readily. The top 

 of the frame stands at thirty-nine inches from the floor, 

 which is the most convenient height for use. The cylinder, 

 or pump barrel, is screwed to its cap and base by large po- 

 lished steel screws, and is of heavy and highly polished 

 brass, securely bolted to the bottom board of the table. The 

 piston rod is of steel, working through a packing box, air 

 tight, in the cap of the cylinder, projecting above the upper 

 board and moving in a socket attached to the frame, which 

 has a square opening for this and the parallel motion, which 

 is connected with the piston rod and end of the lever. The 

 lever is of wrought iron, polished or handsomely japanned, 

 is three feet long, and supported by a steel axle moving in 

 two stout brass sockets, firmly bolted to the table ; at the 

 end of the lever is a turned handle. The receiver plate is 

 truly ground, and made of brass, or stout glass set in brass 

 mounting ; in the centre of the plate there is the usual 

 screw by which apparatus is connected ; beneath which a 

 brass connecting pipe having a stop-cock, passes to the 

 bottom board of the table, where it is terminated in a socket, 

 having a pipe running lengthwise with the bottom board of 



