PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 581 



that it is the finest coal known, except perhaps Breckenridge, 

 which is very similar. 



Open burning coal leaves a white ash, and requires but little 

 attention to keep up a good fire, as a small quantity will keep in. 



Non-bituminous coal consists entirely of carbon, there may be 

 a trace of hydrogen, but not more ; it emits no flame and aff'ords 

 no gas, the fracture is smooth and the lustre bright, it is difficult 

 to kindle, does not soil the fingers, and makes, when thoroughly 

 ignited," a very hot fire. 



Coke is made from coal by depriving it of its hydrogen, con- 

 sequently it will neither emit flame or smoke, but gives out a 

 radiant heat, and leaves a large quantity of ashes. It possesses 

 the quality of charcoal to a certain extent, and gives out carbonic 

 acid gas, which, if the draft in the chimney is not good, falls into 

 the apartment. 



Peat is a vegetable production that is often used for fuel, its 

 smoke is penetrating, and affects the eye seriously ; the odor 

 given off is disagreeable owing to pyroligneous acid. If used for 

 cooking, an empyreumatic smell will be perceived connected 

 with everything it comes in contact with, which is esteemed by 

 some. If properly built up it makes a cheerful blaze, and diffuses 

 considerable warmth, about one-fifth as much as an equal quan- 

 tity of charcoal. 



Atmospheric air plays an important part in the complete com- 

 bustion of fuel ; the air admitted should be in equivalent pro- 

 portions to the material employed, or in other words in mechani- 

 cal relation to the gases with which it is to combine, and time 

 given for union chemically speaking. Whenever there is incom- 

 plete combustion there will be smoke. There is immense waste 

 in this city, and at the large depots of coal of the dust, and 

 small particles, all of which might be mixed with an equal weight 

 of clay, and sufficient water, to admit of being worked into cakes, 

 which when dried will burn I'onger, and give as much heat, as 

 coal in the crude state. This fine coal may be mixed with peat, 

 sawdust, bitumen, and any other inflammable matter, and become 

 useful in steam engines. 



Cow dung makes a good fuel when mixed with mud, or straw, 

 or in fact any dry plant, and is much used in Egypt, Persia and 

 Arabia, where other substances are scarce. 



In Sweden, sea weeds and other marine plants, driven on shore 

 by the wind, are dried and used for fuel. 



