74 DIRECTIONS FOR PERFORMING 



tion may be poured into the jar, and then the jar shaken, so 

 as to permit the water to absorb the gas. The candle may be 

 simply stuck upon the end of a bent wire, but it is much 

 neater to have the tinsmith fit a little cup for its reception, as 

 shown in the figure. 



2. The worn-out watch-springs which can be obtained 

 gratis of any jeweller, may be easily straightened by draw- 

 ing them between the fingers. If the end of each spring be 

 heated and then pounded with a hammer on any smooth 

 hard surface, the temper may be thoroughly drawn and the 

 edge sharpened. Make a slit with a knife in the side of a 

 match, : nto which insert the edge of the spring. Take a 

 piece of zinc or tin large enough to cover the mouth of the 

 jar containing the oxygen, and make a hole through it with 

 a nail. Pass the other end of the spring through this hole, 

 and then through a thin cork. The spring is now ready for 

 burning. The metal cover will prevent the flame from roming 

 out of the jar and burning one's hand, and the cork will hold 

 the spring in its place. When the match is ignited, and then 

 lowered into the jar of oxygen, the spring should not reach 

 more than half-way to the bottom, and should be pushed 

 down as it burns. If a specie-jar be used, do not fill it quite 

 full of gas, as a little water left in the bottom will prevent the 

 melted globules of iron from breaking the glass. 



23. I. If brimstone be used in this experiment, and it fails 

 to light readily, pour upon it a few drops of alcohol, and then 

 ignite it. 



2. If you have not a deflagrating spoon to contain the phos- 

 phorus, one may be readily extemporized. Hollow, a small 

 piece of chalk and attach it to a wire, which may then be se- 

 cured to a metal top, as in the case of the watch-spring. 

 This need not be pushed down into the jar as the burning 

 progresses. , At the close of the experiment, test for the acid 

 formed in the combustion. The fumes are very disagreeable, 

 and should not be inhaled or allowed to escape into the room. 



3. If a piece of bark charcoal be ignited, and then lowered 

 into a jar of oxygen, it will deflagrate with bright scintilla- 

 tions. 



31. I. Put in an evaporating-dish a little starch; cover if 



