OF PNEUMATIC APPARATUS. 



187 



FIG. 2193. 



2188. TATE'S AIE PUMP, of extra large size, for easy and rapid action, worked by 

 winch, crank, and fly-wheel, with 12-inch, upright barrel, of 2|-inch. bore 

 and 6-inch, stroke, the valves working in oil, with iron framework, polished 

 mahogany stand, 10-inch, raised plate, syphon gauge, and ascending mercurial 

 gauge of 33 inches . .. . . . 19 



With, this pump a vacuum to within quarter of an iuch is easily obtained in large vessels 

 within five minutes, by which it is found of much value in many preparations connected with 

 the arts and manufactures. 



2L89. A Small Portable Barometer^ to accompany the above, for comparison with 

 the ascending syphon gauge when required . . 1 5 to 2 10 



2190. DOUBLE BAEEEL AIE PUMP, with 5^-inch. plate and clamp . 3 10 



2192. 6* . 440 



2193. AIE PUMP, double barrel 6^ inches long by 1^-inch. bore, 5-inch, stroke, and 



8 inch, plate, on mahogany stand, with stop-cock (fig. 2193) 8 10 



2194. DITTO, without gauge plate, gauge, and key . . . 7 10 



2195. AIE PUMP, double barrel 7 inches long, with If inch, bore and 5f inch, stroke, 



10-inch, plate, on mahogany stand with pillars, small gauge plate, sypho n 

 gauge, clamp and key, very perfect and handsome . . 12 12 



2196. Treble Barrel Air Pump, being the most improved arrangement for rapid 



exhaustion at lectures, or the more perfect vacuum required in delicate re- 

 searches, with 7-inch, upright barrels, of If-inch. bore and 5|-inch. stroke, 

 10-inch, plate, with raised pillars, and syphon gauge, on mahogany stand, 

 with Tate's single horizontal barrel in addition for very accurate exhaustio n, 

 very handsome . . . . ... 17 



In this admirable arrangement large receivers are quickly exhausted in the ordinary, way 

 till the mercury falls, say to $ or inch, when Tate's attached horizontal barrel is brought into 

 action and the exhaustion reduced by it to, say l-10th or l-20th of an inch at temperature 60> 

 or even more at lower temperatures. 



