486 



NEGRETTI AND ZAMBRA, HOLBOKN VIADUCT, E.G., 



FIG. 2970. 



FIG. 2995. FIG. 2961. FIG. 2952. FIG. 2951. 



2966 Spiral Metallic Thermometer, of larger size, see page 460, Used for Alarm 



purposes, &c. 



2967 Hope's Apparatus for determining the Maximum density of Water, consists 



of a cylindrical glass jar, with an external Copper vessel for holding a 

 mixture of Ice and Salt, and two Thermometers with projecting bulbs, 

 with attached scales, as shewn in the engraving, fig. 2967. See Ganot- 



Price 14 



2968 Apparatus to show that liquids expand by increase of temperature and 



bceome of a lighter specific gravity, consisting of a large glass tube, closed 

 at one end, for holding water, on which floats a small hydrometer adjusted 

 to a temperature of 60. Upon warming the water over a spirit lamp the 

 hydrometer will sink ; but it will rise to the surface when the water cools 

 to 60 10 6 



2969 Apparatus for showing the varying Expansion of Liquids, and the construct- 



tion of Thermometers. It consists of five large Thermometer tubes, partly 

 filled with Mercury, Alcohol, Ether, Oil, and Water ; arranged on a stand 

 with tin trough. Graduated scales are fitted to each tube, by which the 

 relative expansion of the liquids in a given time can be observed, when the 

 trough is filled with hot water . Price for Lecture Table size 330 



2970 Cryophorous, or Frost Bearer, (fig. 2970, Dr. Wollaston's), is a glass tube 



with large bulbs at each extremity, as fig. 1948. These bulbs and tube are 

 nearly exhausted of air, and a small portion of water, about half filling one 

 bulb, left in it. If the empty bulb be surrounded with a mixture of 

 pounded ice and snow the rapid evaporation taking place from the surface 

 of the water will cause it quickly to freeze . .046 066 



2971 Apparatus for showing the Conducting power of 



various metals 10 6 



2972 Cylinder of Wood and Brass, to show Conduction by a 



strip of paper 036 



2973 Parabolic Reflectors, of highly polished zinc, for 



Experiments on Radiant Heat . . . per pair 440 550 



2974 Stands for ditto with simple adjustment . per pair 140 



