ON THE UTILIZATION OF WASTE. 409 



by a philosophical process, which I need not describe just now, is suffi- 

 cient to produce a large quantity of heat, and savage tribes have been 

 accustomed to use that friction to obtain a source of light. For a long 

 time, as many of our older readers will recollect, our only means of 

 obtaining an instantaneous light, even within my own recollection, was 

 the tinder-box. The tinder-box with its trio, burnt-rag, flint, and steel, 

 was familiar to many of us. These were used to obtain a flame, and then 

 in addition to this trio there was the sulphur-match, which was ignited 

 after the flame had been obtained by the sparks falling among the 

 burnt-rag. If the rag were not damp, and everything was in perfect 

 order, you could get a light in a short time ; but if the rag were at all 

 damp, or the day was draughty, you might get a light in a quarter of an 

 hour. There, now we have got a light, and by blowing it up I may 

 succeed in getting the sulphur match alight. I recollect when I was a 

 boy remaining for at least half an hour in a castle which I was to be 

 shown over, whilst a light was got in this way. 



Dobereiner's Lamp. — The first invention which led the attention of 

 chemists to the importance of a means of obtaining an instantaneous 

 light occurred in 1820, when Dobereiner produced a lamp of an elegant 

 character. You 'wall see it rej^resented in this diagram. Here is a 

 vessel in which hydrogen gas is collected. The hydrogen gas is formed 

 by the action of sulphuric acid and water upon zinc. These acting upon 

 the zinc produce hydrogen, and the hydrogen rises here, and as it is 

 formed it expels the acid from the vessel, so that it no longer acts upon 

 the zinc. I have in this way a reservoir of hydrogen ; and now if I take 

 a piece of spongy platinum, which has the power of absorbing oxygen 

 from the air and condensing it within its pores, and bring this platinum 

 in contact with the hydrogen, you see that it gets red hot, and ignites 

 the hydrogen. Thus, you see that this plan of applying hydrogen for 

 the purpose of acting upon the oxygen condensed in spongy platinum is 

 a method by which a light can be obtained. The spongy platinum 

 absorbing oxygen, presented oxygen to the hydrogen, and caused the 

 formation of water, and in the formation of water, so much heat was pro- 

 duced that the hydrogen became ignited, and a light was obtained. One 

 disadvantage which prevented it being universally adopted was simply 

 this : that the least speck or fouling of this spongy platinum puts the 

 lamp out of order. For instance, this may have been in order five 

 minutes ago, and it may be out of order now. Some dust or dirt may 

 have got upon the spongy platinum. Still, the application was so ele- 

 gant that it drew the attention of scientific men to the importance of 

 getting an instantaneous light. 



The next invention consisted in mixing phosphorus and sulphur in 

 a bottle, and then taking them out upon a splint of wood, which was 

 rubbed, and a light obtained in that way. 



Then came the method of getting a light by means of chlorate of 

 potash and sulphuric acid. Here I have some chlorate of potash mixed 

 VOL. III. N N 



