CHEMICAL APPARATUS. 



93 



Different Fluids Expand Un- Fi - 551 



equally. (Fig. 551.) The ap- 

 paratus for illustrating this ex- 

 periment consists of three glass 

 tubes with bulbs on their ends 

 of exactly the same size, and 

 filled with different liquids to 

 the same height. A may be 

 filled with alcohol, B with 

 water, and c with sulphuric 

 acid, to each is fixed a scale ; 

 they are suspended in a tin 

 trough, and when hot water is poured in, the fluids will be 

 found to rise to different heights, according to their expansi- 

 bility ; the alcohol will be the highest, the water next. 



Price, with 16-inch tubes, $4.00. 



The Conductometer.(Fig. 552.) 

 The conductometer is an instrument for 

 illustrating the relative conducting power 

 of different metals, and consists of a 

 circular plate of brass, with a hole in the 

 centre, the edge perforated with holes 

 into which are inserted rods of different 

 metals, of the same size and length, each 

 having a small cavity in its extremity 

 for holding a piece of phosphorus; on 

 hdlding the plate over the flame of a 

 spirit lamp, the heat will be conducted along the different 

 metallic rods, inflaming the phosphorus first in that which 

 is the best conductor, and in the others according to their 

 conductibility. The arrangement usually is copper, brass, 

 iron, tin, zinc, lead, and glass. Price, $1.75. 



Expansion of Metal by Heat. (Fig. 553, next page.) 

 This instrument consists of a cylindrical piece of iron, hav- 

 ing a handle adapted to it, and fitted to a piece of metal 

 having the ends bent up, so that it may just pass through 

 lengthwise, and at its ends go through a round hole ; when 

 heated in the fire, it will be too long to pass in one direction, 

 and too thick to pass in the other. Having become cold, it 

 will again fit and pass through as before. The metallic 

 plate is supported on a mahogany base. Price, $1.50. 



