#it tjje Siitolie |,btement 
By Prof. J. F. MAIN, M A., D.Sc., A.I.C.E. 
T he subject of the abateuient of smoke, both that which is 
produced by private houses, and that which arises from 
manufactories, has, within the last few years, become a matter 
of national importance. In the great centres of population, and 
more especially hi London, the prevalence of fogs, which are 
rendered injurious to health by the presence of the imperfectly- 
burned gases arising from the fuel consumed, has forced upon 
the attention of scientific men the desirability of lessening, if 
possible, the magnitude of this grave peril to the health and 
strength of those living in our large cities. 
It was, therefore, to be expected that the National Health 
Society should early take the matter under their consideration, 
and, in the spring of 1880, Mr. Hart, the Chairman of Council 
of that Society, introduced the question to the Society, and was 
requested to take steps to bring the matter into a practical 
form for further proceeding. He communicated with Professor 
Chandler Roberts, Chemist to the Mint, and Professor of 
Metallurgy to the School of Mines, who undertook to make an 
'examination of existing methods of combustion of coal in house- 
hold grates and in furnaces. Shortly after, the Kyrle Society, 
through their treasurer, Miss Octavia Hill, represented that they 
were contemplating steps in the same direction. A joint com- 
mittee of the two societies was then formed, which proceeded to 
