682 TRANSACTIONS OF THE AMERICAN INSTITUTE, 



LIQUID FUEL. 



Bitumens and oils have been employed as fuel, and are found 

 to give out a great deal of heat. Alcohol is frequently used in 

 the lamp form, and the wick never becomes scorched, or wasted, 

 because the spirit in which it is soaked, never rises in tempera- 

 ture higher than 174''. 



Capt. Parry in his expedition to the North Pole used spirits of 

 wine for fuel, and discovered that one pint would heat twenty- 

 eight pints of water, commencing at a temperature of 32'^. Fat, 

 oil, or tallow yields a higher temperature than spirits of wine, 

 but produces much smoke unless several wicks are used or an 

 Argand lamp. The Esquimaux and Greenlanders produce all 

 their heat by use of lamps, with wicks made of moss. 



When coals are heated to ignition in an iron retort, they decom- 

 pose as followg, the moment the iron appears red, coal tar distils, 

 as the heat increases tar, ammoniacal liquor and sulphurous acids 

 are produced from the pyrites of the coal, if the heat is still in- 

 creased . the gaseous production diminishes, and coke only re- 

 mains. 



The nature of the combustion of fuel until illustrated by mod- 

 ern chemistry was never understood, all opinions respecting it 

 before were erroneous if not absolutely absurd. 



Atmospheric air is indispensable to the combustion of any kind 

 of fuel ; it is an invisible substance, owing to its transparency 

 and want of color; from the same reason, water is no doubt in- 

 visible to the fish that swim in it. 



Wind is a current of invisible air, and the tornado in my 

 opinion is electricity or lightning. 



I must now explain how fuel and air are affected by combus- 

 tion. A combustible body must be kindled before it can burn, 

 or in other words be brought in contact with an actually burning 

 Substance to be affected by heat. 



When charcoal is made red hot, the air surrounding it is de- 

 composed by the carbon uniting with oxygen, which forms car- 

 bonic acid gas, the consequence of light and heat. 



To ignite wood or coal is much more difficult than to ignite 

 charcoal, because they are composed of three more principles 

 which the heat must separate, and form carburetted hydrogen gas 

 which joins oxygen and produces flame and water, the latter is at 

 once dissipated in the atmosphere. After the kindlings used 

 have become ignited, the usual practice is to throw on a large 



