EXPERIMENTAL METHODS IN WATER- AND SEWAGE- WORKS 33 



municipal reports and by the Royal Commission on Sewage Dis- 

 posal shows what a fund of knowledge has been accumulated at 

 London, Salford, Sutton, Exeter, Burnley, Accrington, Hudders- 

 field, Leicester, Birmingham, Bradford, Devizes, Hanley, and other 

 cities, and which for most places has been obtained with almost 

 no special fund devoted to testing purposes, comparatively speaking. 



At Leeds the unusually thorough sewage tests made during the 

 past eight years received appropriations of about $150,000, some 

 two-thirds of which has been actually devoted to that purpose. 

 Manchester has also expended quite large sums for experimental 

 purposes, although, for the reasons above stated, the expenditures 

 were by no means commensurate with the information obtained. 

 The Royal Commission on Sewage Disposal in England is under- 

 stood to have an appropriation of about $55,000 for the expenses 

 of its own staff and the traveling expenses of the numerous witnesses 

 who have appeared before it. There are also special river boards 

 and county councils, with excellent technical staffs, which gather 

 many valuable data. 



In France sewage purification has been the subject of experi- 

 mental study, beginning with the labors of Mille in 1868 at Gen- 

 nevilliers. These tests resulted in the establishment of the present 

 sewage farms of Paris. Within the past few years the biological 

 methods of purification have received attention both from the city 

 of Paris and from the Department of Agriculture. The latter has 

 a general supervising control over water and sewage matters outside 

 of Paris, and is devoting an appropriation of about $60,000 to such 

 investigations. Thus far these studies have been made by Professor 

 Calmette at Lille, as set forth in his interesting progress report of 

 last autumn. 



In Belgium the government is paying particular attention experi- 

 mentally to the treatment of trade wastes at a special station devoted 

 to that purpose at Verviers. 



The government of Holland established, in 1904, a sewage-testing 

 station at Tilburg, the cost of which to date is approximately $15,000. 

 No reports have yet been published. Several ozone plants have 

 been tested in Holland, and the city of Rotterdam is now arranging 

 to test a mechanical filter on the local river- water supply. 



