TEACHING APPARATUS. 1033 



Water Hammer, to be exhausted by the air-pump. 



Water Hammer ; fall of water in a partial vacuum. 



Wollastons Cryophorus, to freeze water by effects of evaporation. 



Sound. 



Sonometer or Monochord, simple form with violin bow. 



Sonometer or Monochord, superior construction, with violin bow, for 

 experiments on vibrating wires. 



Savarf 's toothed wheels, for use with whirling table, to produce tones. 



Paper Disc, perforated, to act as a Syren. 



Syren, simple, without counter, can be worked by a cheap rubber foot 

 blower. 



Syren, with counter, can be worked by a cheap rubber foot blower. 



Organ Pipe, with resonance box. 



Resonance Box, with movable piston to explain effect of length of air 

 column. 



Pair of Lecturer's Tuning Forks, in Unison. 



Chladni's Vibrating Plates, a set of three, in brass, with bow, to show 

 figures of vibration. 



Chladni's Vibrating Plates, a set of ten in glass, with bow and clamp to 

 hold them. 



Hopkins' Forked Tube, to exhibit interference. 



Speaking Trumpet, model of. 



Hydrogen Flame, which sings when burning in the glass tube. ' 



Common Gas Jet, which sings when burning in the glass tube. 



Sound Waves, propagation of, apparatus to explain. 



Heat. 



Fergussoti's Pyrometer, to show unequal expansion of various metals. 



Compound Bar of iron and copper, which bends when heated, to explain 

 effects of unequal expansion. 



Set of Bulb Tubes, to exhibit the unequal expansion of different liquids. 



Bar of Iron and Copper, to explain unequal conduction of heat. 



Ingenhouz's Apparatus, to show unequal conducting powers of various 

 substances. 



Cylinders of various metals, proving the unequal conducting powers of metals,, 

 and their capacities for heat. 



Apparatus to break an iron bar by contraction of heated bar. 



Unequal Absorption, by bright and dull surfaces. 



Reflectors, pair of silvered copper, for concentrating rays. 



Leslie's Cubes, to explain effects of different surfaces in radiation. 



Leslie's Differential Thermometer, cheap form. 



Count Rumford's Differential Thermometer, improved by Matthieson and 

 Griffin. 



Metal Tube, in which water can be boiled by the friction of wooden boards. 



Wollastons Steam Engine, glass model of, showing expansion and condensa- 

 tion of steam. 



Iron Bottles, very thick, which burst when water is frozen in them. 



Hope's Apparatus, to show when water reaches its maximum density. 



Pulse Glass, showing expansion of spirit vapour under diminished pressure. 



Prince Rupert's Drops, unannealed glass, showing effect of unequal con- 

 traction. 



Candle Bombs, containing spirit, the expansion of which causes explosion. 



Dr. TyndalVs Apparatus to show water boiling at a low^jr temperature 

 under a reduced atmospheric pressure. 



