PETER SPENCE 275 



" Perfect freedom from smoke would, if 

 accomplished, only increase the evil arising 

 from the purely gaseous results of combustion"; 

 and again : " While demonstrating that to the 

 mere economist, there is great inducement to 

 get rid of all visible smoke, as a consequence 

 of his obtaining perfect combustion of fuel, 

 I would at the same time say to the sanitary 

 smoke consumer, that he had better not 

 interfere further, as every step he takes in 

 enforcing the consumption of smoke, will 

 only tend to deteriorate the atmosphere, and 

 that every cloud of visible smoke he is 

 successful in dispelling, is only making 

 way for a more baneful, though invisible 

 agent." He regarded carbonic acid, car- 

 bonic oxide, and sulphurous acids, as far 

 more prejudicial to health than visible smoke; 

 indeed, he believed soot to have an antiseptic 

 influence, and to be beneficial rather than 

 prejudicial. 



From the economical standpoint he did not 

 advocate permitting imperfect combustion, 

 but he would construct arrangements that 

 would ensure that all ammonia would be 

 condensed and converted into sulphate of 

 ammonia, and such gases as could not be 

 condensed and utilised should be carried up 



