476 



NEGBETTI AND ZAMBRA, EOLBOKN VIADUCT, E.G., 



FIG. 2900* 



6-in. 



12s. 6d. 



8-in. 



15s. 6d. 



FIG. 2901. FIG. 2900. 



2903 Cylindrical Shaped Receivers, Open (fig. 2846) 



Diameter 4-in. 5-in. 



6s. 6d. 7s. 6d. 



2904 Tall Cylindrical Glass Receiver, Open (fig. 2878), 



for Guinea and Feather experiment . . . . 16 1 10 



2905 Tall Glass for Fountain Experiment . . 12s. 6d. 1 1 150 



2906 Air Gun, complete with condensing syringe, bullet 



mould, &c., in case with lock and key. Made to order. Price 21 



2907 Mariotte's Apparatus, arranged to show that under 



the pressure of two atmospheres air is compressed 

 into half its ordinary volume (fig. 2907) 1 10 



2908 Mariotte's Apparatus, to exhibit that air expands 



to twice its ordinary volume under diminished 

 pressure, equal to half an atmosphere 150 



"Boyle's Law, The law of the compressibility of 

 gases, was discovered by Boyle and Mariotte independently 

 (about the year 1670). In consequence, it is in England 

 commonly called Boyle's law, and on the Continent, 

 Mariotte's Law. This Law is as follows : The temperature 

 remaining the same, the volume of a given quantity of gas 

 is inversely as the pressure which it bears. Nos. 2907 and 

 2908 are constructed for verifying this law. 



"In experiments with Mariotte's Tube, as the quantity 

 of air remains the same, its density must obviously 

 increase as its volume diminishes, and vice versa. The law 

 may thus be enunciated : For the same temperature the 

 density of a gas is proportional to its pressure." Hence 

 as Water is 770 times as heavy as Air, under a pressure 

 of 770 atmospheres air would be as dense as water. 



FIG. 2907. 



2909 Sets of Pneumatic Apparatus, packed in case, consisting of single or double 

 barrel Air Pump, open and close receivers, fountain apparatus, pair of 

 hemispheres, sliding wire and collar, syringe and lead weight, bladder, 

 frame, and weight, filter cup and glass for mercury, hand glass and fruit 

 stand . . 5 5s.; 10 10s. ; 21. 



