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BENJ. PIKE'S, JR., DESCRIPTIVE CATALOGUE. 



worked than in the ordinary construction, and being also 

 less fatiguing to the operator. The pump plate is support- 

 ed by four mahogany pillars, on a table elevated about 

 twenty-eight inches. The connexion between the pump- 

 plate and the cylinder is by a brass pipe, having a stop-cock 

 for shutting off the communication when required. The 

 frame is of polished mahogany ; the base twenty-two inches 

 long and fourteen inches wide. Price, $20.00. 



Condensing Apparatus. The condenser is a syringe by 

 which a large quantity of air may be forced into a given 

 space. It is constructed on the same principle as the air 

 pump ; only the valves are disposed in the contrary order, 

 that is to open inward instead of outward. 



Fig. 185 represents a syringe fur- 

 Fig. 185. nished with a handle, moving a solid 

 piston air-tightly in a cylindrical 

 barrel, which barrel is furnished with 

 a valve at the foot, and either a 

 small hole near the top of the barrel, 

 or else the piston, instead of being 

 solid, is perforated, and has a valve 

 also opening downwards. It will be 

 evident, that working the handle up 

 and down will alternately fill the 

 barrel with air from the upper part, 

 and condense it into any vessel at- 

 tached to the screw at the foot. 



The air vessel is a strong globular 

 shaped glass vessel, supported on a 

 foot, having a neck to which a brass 

 cap with stop -cock is fitted ; to the 

 stop-cock is fastened a pipe, reaching 

 nearly to the bottom of the vessel ; 

 to the upper screw of the stop-cock 

 is attached a tube, and a variety of 

 jets ; one a plain jet, one a globular 

 jet, pierced with many holes, another flat on top pierced 

 with a cross ; also, there is usually accompanying them, a 

 revolving jet, as represented in the cut, which may be moved 

 either for air or water. To use, the vessel is about half 

 filled with water, and the condensing syringe being screwed 

 to the tube, and the stop-cock opened, air is to be forced 



