STERILIZATION 



199 



(d) The loss of manurial matter as nitrogen and carbonic 

 Lcid. 



(e) The low value of the products, ash and clinker, and the 

 jxpense of their removal. 



The accumulations could be greatly reduced, and their 

 character made more tractable, if every householder would 

 follow the advice repeatedly given to burn all his vegetable 

 refuse in the kitchen fire, and throw little besides clean ashes 

 in the dustbin, also by the regulations enforced on the Con- 



[tinent and in many places in England against littering the 

 jtreets. 

 Town refuse may be roughly divided into that derived from 



\streets, from houses, and from trades, the latter, according to the 

 Public Health Act, having to be separately paid for. House 



(refuse is known to be of most miscellaneous character, both in 

 regard to organic and inorganic constituents. In London the 

 "fairly combustible matter " in the refuse is said to be 64 per 

 cent., in Edinburgh 26 per cent. The average total weight for 

 London in 1895 was stated to be " about i ton per annum for 



[every four inhabitants, or 1,250,000 tons for the whole area." 



JThe old style of house dustbin was as insanitary as the collec- 

 tion by dustmen was formerly dirty and careless. Many types 

 of portable covered metallic bins, with daily collection, are in 

 use both in London and the provinces. 



After the failure to profitably utilize the nitrogenous matters 

 of refuse as manure, its carbonaceous constituents were still 

 available by burning as sources of heat, after drying. Modern 

 dust destructors, therefore, dating from 1876, generally include 

 some arrangement for steam raising and electric light, with a 

 view to saving to some extent the cost of destruction. But the 

 aspect with relation to health must always be the first con- 

 sideration. 



Modern dust destructors must fulfil the following conditions : 

 I. A temperature not lower than 1,300° F. : in good forms 

 1,600° to 1,800° is reached, and with forced draught by a steam 

 jet or fans up to 2,000° F. can be in many cases attained by 

 the burning of the refuse itself. The earlier forms were of low 

 temperature type, reaching only 750° to 1,000° F. in the main 

 flue or combustion chamber. This was not sufficient to deal 

 with the effluvia, the destruction was often imperfect, and the 

 resulting clinker, instead of being hard, was soft, friable, and 

 sometimes even putrescible ; indeed, it was not uncommon for 



