194 



L. CASELLA'S CATALOGUE 



2276. TANTALUS CUP (fig. 2276), p. 190, consists of a glass vessel with a carved figure, 



having a syphon concealed in the hody ; when water is poured into the vessel, 

 level with the chin of the image, it is immediately emptied hy the syphon 



8 6 to 12 



2277. CYLINDRICAL GLASS JAR, containing water and a delicate hollow glass balloon 



or figure floating in it, with air-tight cover to the jar. This pleasing philo- 

 sophical toy illustrates most of the laws of fluidity 7 to 14 



2278. Centrifugal PillilJ), for raising water by centrifugal and atmospheric pressure, 



in which a fan is made to revolve that gives rotation to the water, the centri- 

 fugal power of which drives it up the tube . . . 440 



2279. FORCING PUMP (working model), with glass barrel, exhibiting also the operation 



of the fire engine . . . . . . 220 



2280. LIFTING- AND FORCING PUMPS, together, on high mahogany stand, with cisterns 



for supplying water . . . . . .-220 



2282. HOUSEHOLD LIFTING PUMP (working model), with glass barrel ; the escape valve 



is here placed within the piston, so that the same barrel raises the water in a 

 continued line, and the piston thus raised rests on the fixed valve when 

 depressing it . . . . . 17 6 and 1 10 



2283. CAPILLARY ATTRACTION, shown by a set of tubes, with bores of different dia- 



meters, mounted 6 6 



2284. A Set of Four Tubes, serving to illustrate the tensions of aqueous vapour, and 



of the vapours of alcohol and ether, which are respectively seen by the 

 heights at which the mercury stands in three of the tubes as compared with 

 that in which no vapour exists . . 18 6 to 1 5 



2285. MARIOTTI'S TUBE, on stand, illustrating his admirable law of the compression 



of elastic fluids . . . . 10 6 to 1 5 



2286. HYDROSTATIC BALANCES with steel or brass beams, in neat mahogany cases, with 



all requisite apparatus for determining the specific gravity of both liquid and 

 solid bodies, 3 3s., 4 14s. 6d., 8 8s., and . . " 16 16 



* # * Hydrometers, etc., see specific gravity instruments, pages 212 to 217. Current meter, see 

 p. 71. 



FIG. 2287. 



IMPROVED DIVING APPARATUS, 



For deep-sea work, pearl or coral fishing, sponge diving, construction of bridges, 

 embankments, breakwaters, etc. The fig. 2287 represents an important application of 

 this apparatus employed in recovering the guns from the wreck of the " Royal George," 



