186 L. CASELLA'S CATALOGUE 



2176. Air Pump, sloping barrel, 9 inches by If, 5|-inch. plate, bell glass receiver, and 



stop-cock, to retain a vacuum when removed from the pump, on mahogany 

 stand (fig. 2176), p. 189 250 



2177. Tatc's Double Action Air Pump, with 2 pistons in one barrel, for exhausting 



or condensing purposes. On this plan the air is drawn from the receiver in 

 the centre of the barrel, and expelled at the two extremities, the exhaus- 

 tion being more perfect than can be obtained by any other arrangement. 

 Length of barrel 16 inches, bore If inches, stroke 8| inches, size of plate 



7 inch, diameter, mounted on stout brass clamp, with key, syphon gauge, 

 and screw piece for connecting flexible tube, complete . 3 14 



An excellent instrument, will exhaust in a receiver of 80 cubic inches to l-10th inch, and 

 readily freeze water over sulphuric acid in a receiver of 300 cubic inches. 



2178. BELL GLASS KECEIVER, for ditto . . . . 056 



2179. Tate's Improved Air Pump, size and form as above, but mounted on a solid iron 



plate, with 4 legs, for screwing or clamping to the table, with syphon gauge 



3 14 



SEPAEATE APPLIANCES, if wanted, as on fig. 2186, p. 188, viz. 



2181. CLAMP (j) . . - . . . . . 036 



2182. EXTRA SCREW between the pump plate and the stop-cock, for connecting extra 



plate (H) when required, with spare nut . . 036 



2183. Extra Plate (H), of cast-iron, with three legs, very convenient for drying 



chemicals in vacuo, or freezing water over sulphuric acid, with plate -glass 

 surface, air tube, and stop-cock, complete, as shown by G- F, three sizes, viz., 



8 inch., 14s. 6d. ; 10 inch., 18s. 6d. ; 12 inch. . ^ 1 5 O 



2184. FLEXIBLE CONNECTING- TUBE (E), 3 feet, best wired, with screw (D) adapted for 



the joint and stop-cock . . . , . . 056 



2185. FLEXIBLE CONNECTING TUBE, if with stop-cock . ' . 080 

 The exhaustion of either of the separate plates is shown by the attached syphon gauge. 



One connecting tube serves for any number of the separate plates, each having a stop-cock 

 to retain the vacuum C fig. 2186). 



2186. Tate's Double Action Air Pump, for exhausting or condensing, as above, with 



extra fittings, viz., screw for adapting flexible tube to the pump, 1 extra 

 plate 8 inches diameter, with stop-cock, pan for sulphuric acid, connecting 

 tube and joint, flat glass receiver 6|- inches diameter, glass capsule for evapo- 

 ration in vacuo as Leslie's experiment for freezing water, etc., with strong 

 iron clamp, complete (fig. 2186), p. 188 . '_'-;' '-,. , 515 



2187. TATE'S AIR PUMP, as above, but about double the size and power, with 17-inch. 



barrel, of l|-inch. bore and 9^-inch. stroke, mounted on strong iron stand 

 with iron legs, etc., 10-inch, plate, with extra joint and arm, and syphon 

 gauge, being the largest and most powerful form of Tate's pump which can 

 be worked without rack-work or other mechanical arrangement 880 



