72 



Accepting this classification as a convenient one for tlie purpose in 

 hand, we may inquire as to the process hy which the smoke now being 

 delivered by each of the several groups is to be eliminated. 



3. Large Fires Such as Are Employed in Metallurgical Processes. 

 Except in a few cities, of which Pittsburg is the best type, the proportion 

 of the total smoke delivered from such fires is small. In the city of Indi- 

 anapolis, for example, it is exceedingly small. ^Moreover, the managements 

 of industries using such lires are, in many cases, finding increased efficiency 

 in operation by the installation of gas producers which receive the coal and 

 deliver highly heated gas for use in the furnaces. The gas producer makes 

 smokeless the process of converting coal into heat. As its use under a wide 

 range of conditions will result in economy in operation, no injury would 

 be done by the prohibition of smoke from all fires which might properly 

 be served by producer gas. provided a reasonable period is allowed be- 

 tween the passage of the prohibitive ordinance and its going into effect. 

 Fires of this group which can not be thus treated in such cities as In- 

 dianapolis will be so few that their effect will be negligible. 



4. Large Boiler Plants. The suppression of smoke from fires of this 

 class by the adoption of a suitable automatic stoker, will effect aw economy 

 in operation, hence owners will not seriously object if they are required, 

 after suitable notice, to so eciuip their plants. An ordinance requiring all 

 boiler plants of more than oOO horse-power to be thus equipped within three 

 years of the date of its i>assage would not be imreasonable. 



5. l:^mall Boiler Plants and Small Industrial Fires. Referring first 

 to boiler plants, it should be noted that the fires of this group are or- 

 dinarily prolific sources of smoke. Boilers of 100 horse-power or less are 

 all over the modei'u city. Generally speaking, no economy can result from 

 the application of automatic stokers to these small boiler plants and hence 

 owners can not be infiuenced to add to their fixed charges in the expecta- 

 tion of securing a money return. The requirement that such furnaces em- 

 ploy anthracite coal, coke, or other smokeless fuel, would in all cases work 

 serious hardship and in many cases it would be prohibitive. The wisest 

 and most effective course to follow with reference to such fires is to pro- 

 vide a satisfactory substitute, then abolisli them. So far as such plants are 

 now employed in the production of power, they can he rendered unneces- 

 sary through the cheaper and more effective distribution of electrical 

 power. So far as steam from such boilers may at present be used for heat- 

 ing they can be rendered of no effect through the supply of heat from a 



