488 



NEGRETTI AND ZAMBEA, HOLBOEN VIADUCT, B.C. 



FIG. 2967. 



FIG. 2983. 



2991 



FIG. 2993. 



s. d. 



Apparatus to exhibit the principle of Ventilation, 

 showing an ascending current of heated air and a 

 descending current of cool air to supply its place (2991) 12 6 



Fine Wire Gauze, for experiments on Flame, demonstrating its inability 

 to pass through a medium formed of Metal Threads, owing to their 

 cooling or conducting power, for explaining the theory and action of 

 Davy's Safety Lamp, 8 inches square 020 



Improved Safety Lamps, Universal Clanny, with Swivel and elastic ring, to 

 allow for expansion of the Glass (fig. 2993*) . . 17s. 6d. 1 5 



Glass Apparatus, for exhibiting the evolution of latent heat by a mixture 

 of two cold fluids. The glass vessel is partly filled with "Water, and upon 

 its surface is floated a small light capsule, into which a little piece of 

 dry Phosphorus is placed; now if strong Sulphuric Acid be carefully 

 poured into the water, sufficient heat will be produced to ignite the 

 Phosphorus 086 



Bunsen's Ice Calorimeter, for experiments on Specific Heat, (fig. 2995, 

 see Ganot) 6 15 



Various other experiments illustrating the Phenomena of Heat, see Chemical 

 Section. 



2992 



2993 



2994 



2995 



FIG. 3005 e 



FIG. 3009. 



* See also page 404. 



