PREFACE TO THE THIRD EDITION 



A Third Edition being called for by my Publishers, I have 

 been able to incorporate the further experience which has 

 been gained in the bacterial methods of sewage disposal during 

 the past five years, and have embodied the conclusions of the 

 Royal Commission so far as they have been published. We 

 still await their final report, and, in England, hope that legisla- 

 tion will follow such report, in order that Local Authorities may 

 have free scope in developing the newer methods of sewage dis- 

 posal. The Local Government Board have relaxed some of 

 the rules which had proved irksome in many districts, but as 

 unfortunately works approved by them, and constructed out of 

 loans on deposited schemes, have in certain cases given rise to 

 serious complaints and law-suits, I hope that in the future it 

 will be possible in England for Authorities to carry out works 

 which are likely to be more successful, if the expert, after or 

 during construction, is allowed to make such modifications in 

 design or working as in his opinion will result in a proper 

 disposal. 



I have to thank, as in former editions, many firms for lending 

 me blocks. I am also indebted to the Main Drainage Com- 

 mittee of the London County Council and the Controller of 

 His Majesty's Stationery Office for lending me the Plates for 

 Figs. 4-12, 15-18, from Dr. Houston's Report and the 2nd 

 Report of the Royal Commission on Sewage Disposal. 



Samuel Rideal. 

 28, Victoria St., Westminster, 

 November^ 1906. 



