2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 76 



which, to be effectively operated, is at all times concerned with three 

 important factors : 



(i) The use of proper ingredients, 



(2) In the proper proportions, 



(3) Under the proper conditions. 



By this is meant using the right coal under adequate furnace con- 

 trol and with the proper design of furnace installation. More 

 specifically, the three issues involve: (i) The quality of coal, (2) 

 furnace control, and (3) furnace installation, and will be taken up 

 for discussion under these three general headings, but in reverse order. 



FURNACE INSTALLATION 



The manufacture of furnaces and boilers is a major industry in 

 itself, composed of large organizations engaged in active competi- 

 tion and each having its own corps of highly trained experts. 

 Exhaustive studies of combustion and heat absorption have been 

 made not only under research conditions but under operating condi- 

 tions as well. As a result, furnace and boiler designs have been devel- 

 oped which may be taken as embodying the best principles and suited 

 to all ordinary requirements. This being the case, in the matter of 

 furnace installation the consumer need scarcely concern himself 

 beyond determining whether it is of standard design, reasonably 

 up to date, and reasonably in keeping with the requirement. 



FURNACE CONTROL 



To appreciate the need for furnace control it is necessary to tmder- 

 stand something of what takes place within the furnace. Reference 

 has already been made to the combustion of coal as being a chemical 

 reaction. Precisely speaking, it includes a number of reactions, in- 

 volving the several ingredients composing coal, but inasmuch as 

 carbon is the major ingredient, in the interest of simplicity, attention 

 will be confined to its activity within the furnace. 



When carbon burns it unites with the oxygen of the air in two ways. 

 Expressed chemically, these are 



C-f-02 = C02 

 and 



2C+02 = 2CO 



which means, taking into account the relative weights of the ingre- 

 dients involved, that in the first reaction, 



