470 



NEGRETTI AND ZAMBRA, HOLBORN YIADUCT, B.C., 



2841 



2842 

 2843 

 2844 



2845 

 2846 



2847 



FIG. 2849. FIG. 2848. 



Newman's Improved Single-Barrel Air Pump, for s . a. s. a. 



obtaining a most perfect exhaustion (Council Medal 



awarded, 1851) of large size, with metal valves, 



and Ground Glass Receiver Plate, 13 inches square, 



Mahogany Stool Stand . ... 40 



For description of this Instrument see Catalogue of 1851 Exhibition. 



150 



2 10 330 



076 10 6 



066 12 6 



Single -Barrel Air Pump, with Receiver . 



Ditto ditto larger (fig. 2843) 



Ditto ditto with inclined barrel, raised plate 

 and stopcock (fig. 2844) 



Cylindrical Glass Receivers, closed at the top for 

 single-barrel air pujips ... 3s. 6d., 5s. 



Glass Receivers, open at top with ground welts, as 

 fig. 2346 ; see also Nos 2899 to 2905, page 476. 



Tate's Double -Action Air Pump, having 2 pistons in one cylinder, the air 

 being drawn from the receiver in the middle of the cylinder, and expelled 

 at the two ends. It is mounted on a strong metal clamp and screw, by 

 which it can be firmly attached to any bench or table. The receiver plate 

 is 7 inches diameter, carefully ground ; the cylinder is 16 inches long, with 

 1^-inch bore length of stroke Si-inches. The exhausting power of this 

 pump is very great, and it has a very simple contrivance, by which it can 

 be also used for condensing. Its compact form renders this pump one of 

 the most handy and useful for laboratory purposes. 

 Price, including Syphon Gauge and fittings, without the Receiver 440 



