FUKNACE BLOWERS. 71 



CHAPTER 



THE ABGAND BURNER. 



1$ view of the facts and explanations given in the last 

 chapter, it is easy to understand that one way, at least, of 

 attempting to increase the light given out by any flame is 

 to continue some mode of increasing the supply of oxygen 

 for it without dispersing or scattering the burning materials / 

 in other words, of " blowing" the candle or fire without 

 blowing it out. 



It was a Swiss inventor named Argand who first con 

 trived to do this, and the contrivance which he devised 

 is called the Argand burner to this day. 



But, in order that you may clearly understand the prin- 

 ciples of his invention, I must first say that there are two 

 ways of " blowing" fires in furnaces and forges : one by 

 driving in the current of air by the force of propulsion be- 

 low, and the other by drawing it in, by the force of ex- 

 haustion in the chimney above. 



The former is effected by means of bellows, and some- 

 times by another contrivance called a fan-blower, by either 

 of which a strong blast is forced into the fire at the grate. 

 In some furnaces where a very great heat is required, the 

 air is heated before it is driven into the furnace, so that 

 the full effect of the additional supply of oxygen may be 

 secured without any diminution being caused by the cool- 

 ness of the current of air. 



The latter of the modes above mentioned that is, the 

 drawing of air in by the force of exhaustion in the chim- 

 ney above, is effected by making the chimney very tall. 



