SALTER A CHRISTMAS LECTURE OX COAL 



233 



They are either hydro -carbons or carbo-hydrogens, as the case may 

 be. And then there are acid fats, Rosolic, brunolic, carbolic, &c, 

 which are likely to test the skill and research of our chemists for 

 generations to come. 



We can glance at one or two only of the more important of these 

 substances. 



Paraffine, or napthaline, which, as above said, exists in the coal- 

 naptha, is, however, more profitably obtained by distillation of the 

 celebrated Torbane Hill, or Boghead coal, and some of the Cannel 

 coals, at a dull red heat ; though even at this heat only a portion of 

 the oil can be retained, the rest going off in the form of coal-gas. 

 An analysis of an average specimen of the coal is as follows, side by 

 side with an analysis of the pure paraffin itself: — 



Boghead Coal. 



Carbon 60 to 65 per cent. 



Hydrogen ... 7 J to 9 „ 

 Earthy matter 20 to 25 „ 



100 parts 



Pure Paraffin. 



Carbon per cent. 



Hydrogen 14| 



Loss or oxygen ... f „ 



100 parts 



And by this distillation, paraffin oil, naptha, and pure paraffin are 

 obtained. The oil, as before said, is used largely for machinery, the 

 naptha for light ; so that a railway train may be driven by the coke, 

 lubricated by the oil, and lighted by the naptha obtained from the 

 same cwt. of coal. 



From the oil a crystalline substance, which is true paraffin, is 

 obtained by cooling, and when purified by vitriol, soda, and warm 

 water, yields at last the beautiful candles with which most people are 

 now familiar. We can get oil and spermaceti at last without hunting 

 out and destroying the lord of the polar seas. 



Such oils and candles are made from other bituminous shales in 

 our own country. Those of Caithness are chiefly bituminous remains 

 of Old Red Sandstone fish ! So Miller and Murchison tell us. 

 And his majesty the King of Ava makes most of his pocket-money 

 by sending us the " Rangoon tar" for this purpose. 



The only uses that I know of for creasote are curing ham and 

 toothache ; for the fluid used for " creasoting" timber is not creasote, 

 but pitch-oil. We have done now with these acrid and tarry elements, 

 and must say a word on the scented ethers which are found in coal. 



For, strange to say, in this dark compound of ill savour, lie im- 

 prisoned fairy scents which rival the breath of flowers. Their full 

 history may be found in Ure's New Dictionary of Chemistry, or the 

 original papers by Prof. Hoffmann, in the Philosophical Journal. 

 Prof. Hoffmann himself has been a large discoverer in this, as in all 

 other branches of organic chemistry ; and I have heard an anecdote 

 of these researches worth recording here. A lady whom he had 

 admitted to his laboratory while these essences were being manu- 

 factured, was so charmed with the odour of hyacinth, that she forgot 

 vol. iv. 2 c 



