LECTURE VI 



CARBON OR CHARCOAL COAL-GAS RESPIRA 



TION AND ITS ANALOGY TO THE BURN- 



ING OF A CANDLE CONCLUSION 



A LADY who honors me by her presence at these lectures 

 has conferred a still farther obligation by sending me 

 these two candles, which are from Japan, and, I pre- 

 sume, are made of that substance to which I referred in a 

 former lecture. You see that they are even far more highly 

 ornamented than the French candles, and, I suppose, are 

 candles of luxury, judging from their appearance. They have 

 a remarkable peculiarity about them, namely, a hollow wick 

 that beautiful peculiarity which Argand introduced into the 

 lamp and made so valuable. To those who receive such 

 presents from the East, I may just say that this and such 

 like materials gradually undergo a change which gives them 

 on the surface a dull and dead appearance; but they may 

 easily be restored to their original beauty if the surface be 

 rubbed with a clean cloth or silk handkerchief, so as to 

 polish the little rugosity or roughness: this will restore the 

 beauty of the colors. I have so rubbed one of these can- 

 dles, and you see the difference between it and the other 

 which has not been polished, but which may be restored by 

 the same process. Observe, also, that these moulded candles 

 from Japan are made more conical than the moulded candles 

 in this part of the world. 



I told you, when we last met, a good deal about carbonic 

 acid. We found by the lime-water test that when the vapor 

 from the top of the candle or lamp was received into bottles 

 and tested by this solution of lime-water (the composition of 

 which I explained to you, and which you can make for your- 

 selves), we had that white opacity which was in fact cal* 



