UTILIZATION OF SEWAGE. 61 



secure a profit. They were after mono}', and they found, as 

 the Doctor has told you, that the fertilizing elements of 

 sewage cannot be extracted economically from the water. 

 There is no known means by which you can take ammonia 

 from water except by distillation and absorption in the soil. 

 That is demonstrated, and nitrogen in various forms is about 

 all of the fertilizing? element there is in sewajre. 



There is one point which I think is unsatisfactory in regard 

 to what is called the "A B C Process," for the manufact- 

 ure of guano from sewage. The essayist tells us that they 

 have got a method of making a valuable fertilizer by this 

 means. I know something about that. I have official doc- 

 uments which show conclusively what that fertilizer is worth. 

 The "ABC Process " is called also the Sillar process, and 

 was carried on for a long time near London, by " The Na- 

 tive Guano Company." I have watched its progress with a 

 great deal of interest. They propose by a complicated sys- 

 tem to produce a precipitation of the fertilizing elements in 

 sewage, so that they can take them up in a solid form, mani- 

 pulate them, and make a useful fertilizer for the soil. They 

 occupied public attention about London for a number of 

 years. There was a great deal of secrecy about it, and con- 

 siderable opposition on the part of other manufacturers. 

 The Drainage Commissioners insisted upon it, as a public 

 demand, that they should show their hand ; and finally they 

 were constrained to allow an engineer appointed by the 

 Commissioners to enter-their works, and permit the process 

 of manufacture to be conducted in their presence and under 

 their supervision, to ascertain what was done, and they tried 

 a series of tests to see what it was worth. The result was 

 that they made 142 tons of fertilizing material that was 

 solid, tangible, and could be sent away. Then they put 

 that material into the hands of an agricultural chemist to 

 ascertain its value as a commercial fertilizer. They found 

 that it had cost £6 6s. per ton. They found that its value in 

 the market, according to the cost of the elements contained 

 in it, was 19s. Sd. a ton ; and they could not find any farmer 

 who would haul it off if they would give it to him. That 

 was the end of the Sillar process of making Native Guano, 

 and that is the difficulty with chemical precipitation of sew- 



