68 ANNUAL OF SCIKXTIFIC DISCOVERY. 



most iio2:loclorl, as far us ]n"acticn is ooncoriied. The cost of fuel 

 aiiiuially required iu the Uuitcd States for inoeliauical and mauu- 

 faeturiuii; ])urposcs, and princ'ii)ally for the generation of steam 

 (heaving out of the calcuhition the immense amount used in do- 

 mestie economy), has been estimated at $()0,000,(.)00. Estimating 

 it at only $oO,OUO,000, any improvement which would save even 

 one-quarter of this sum (or $12,500,000) would add so much M 

 tiie national wealth, In' largely extending man}' branches of pro- 

 ductive industry, and rendering prolitalile many cntm-prises now 

 languishing and poorly remunerative. The many different kinds 

 of furnaces and boilers now in use, in this country and in Europe, 

 like the many infallil)le cures for dangerous diseases, only show 

 that all are imperfect, and that no one is entitled to the full confi- 

 dence of the public. 



"No one can deny tliat the prevention and consumption of 

 smoke are very desiraljle, both from a sanilai-y and an economical 

 point of view. The princi]}les of chemistry, and practical expe- 

 rience, show that the prevention of smoke and the perl'ect com- 

 bustion of fuel are S3"non}mous ; or, in other words, that smoke 

 is carbon escaping unconsumed from the ehimiKiy, and so much 

 lost fuel. Hundreds of tliousands of tlollars are thus annually 

 thrown away, at a time, too, when strict economy ought to be 

 the rule. It is not exaggerating to say that one-half of the fuel 

 used fur generating steam in this country would, with the use of 

 l^roper furnaces, perform the same service now derived from the 

 whole, as at present used. 



" The idea that we cannot have fire without smoke is not true 

 of a well-constructed furnace, after the fire is once well kindled. 

 Man 3'^ attempts have been made to solve this smoke problem, but 

 all have failed, more or less completely, from inattention to the 

 laws of perfect combustion, the variable products according to 

 the fuel, the want of system in the management of the furnace, 

 and, above all, from the failure to bring the due iiroportion of 

 air into contact with the comljustible gases. Various devices have 

 been employed, both in Europe and this country, to arrest or 

 delay the gases of imperfect combustion in their passage to the 

 chimney, by different kinds of bridges, generally of fire-brick, 

 behind and near the fire ; and various imperfect attempts have 

 beeu made to admit a certain quantity of air behind these bridges, 

 to secure a more perfect combustion, diminishing, however, to a 

 certain extent, the heat by the admission of the cold air. Even 

 with these, in England, there has been secured a saving of thirty- 

 three per cent. 



"As a preliminary to perfect combustion, a proper amount of 

 grate-surface, and a boiler of sufficient size, are of the first neces- 

 sity ; as, with too small a fire-surface, and a boiler so small as to 

 require constant forcing, perfect combustion and its resultant 

 economy are out of the question.'" 



After showing the proper proportions of grate-bars to boiler- 

 surface, the heating properties of various kinds of fuel, and the 

 proper amount of ah* to be supplied for perfect combustion, he 

 goes on to say : — 



