296 LIGHTING BY GAS. 



One would not suppose that such a substance as gas 

 could be packed very easily in any way, and yet Nature 

 has the art of stowing it in a very compact form in all that 

 class of substances which have already been described as 

 hydrocarbons that is to say, in almost all natural sub- 

 stances that are inflammable. It is packed very closely 

 in wood, in all bituminous coal, and in all such substances 

 as resin, pitch, wax, and tallow. 



"Indeed," said Lawrence, pointing to one of the tall can- 

 dles which stood upon the table before them while they 

 were at supper, " providing these candles is only a mode 

 of bringing gas on board in a compact and manageable 

 form. The paraffine of which these candles are made is a 

 hydrocarbon that is, it is composed chiefly of hydrogen 

 and carbon combined with each other and packed very 

 closely together. The heat of the burning wick liberates 

 them and restores them to their gaseous form, and they 

 then burn, just as the gas in the cities does from a jet; 

 only, in the case of the candle, the gas is burned directly 

 as fast as it is set free, and in the place where it is set free, 

 instead" of being saved and stored in a great reservoir, and 

 then conveyed in pipes to be burned in different places at 

 a distance from where it is produced. In a philosophical 

 point of view, and in all essential respects, the burning of 

 a candle is the same as burning gas from a jet." 



" That's curious," said John ; " and is it the same with 

 a lamp ?" 



" Precisely the same," replied Lawrence ; " only, in the 

 case of the lamp, the material from which the gas is dis- 

 tilled is a liquid, instead of being a solid, as it is in the 

 case of the candle. 



" Thus, in point of fact," continued Lawrence, " they do 

 burn gas in this steamer. They bring it on board packed 

 very snugly in the paraffine of the candles. They might, 



