UTILIZATION OF SEWAGE. 35 



after which the sewage was allowed to filter across a gravel 

 bed three feet thick. This proved unsatisfactory, as only 

 solid matter was taken out, and the court again interfered 

 with an injunction. A contract was then made with a fer- 

 tilizer company, which agreed to epurate the sewage for 

 fourteen years at $3,750 per year, the company engaging to 

 erect building and machinery, and furnish the necessary 

 tools. An extractor first separates the solid matter. The 

 liquid is then run into cauldrons under the first group of 

 buildings. Agitators mix impure sulphate of alumine with 

 it at a boiling temperature. It is then run into a second set 

 of vessels, where milk of lime is added and thoroughly 

 mixed, then discharged alternately into four reservoirs in 

 the open air, which are cleaned every fourth day. The 

 liquid thus treated comes out sufficiently pure, aud is allowed 

 to filter over about four acres, and finally find its way into 

 the river. Thirty tons of coal, one ton of sulphuric acid, 

 nine tons of sulphate of alumine, and four tons of lime, are 

 used each week. The company's net loss is about $7,500 

 each year. 



After long and costly experiments the greatest chemists 

 have declared that in practice the only manner to epurate 

 sewage is to send it on the laud, which eliminates the pol- 

 luting elements and fertilizing matter for the good of vege- 

 tation and the soil. Dr. Angus Smith, says : "In all cases 

 the best results are obtained by irrigation." And Dr. Car- 

 penter certifies, in a notice read at the International Con- 

 gress, in 1881, " the only way ammonia could be eliminated 

 from sewage is by irrigation." 



A commission, appointed by Parliament, composed or 

 Messrs. Dennison, Frankland and Morton, reported : *'The 

 actual resources of chemistry do not permit the hope that 

 the polluting matter dissolved in sewage can be precipitated 

 and sent away by any appliance of chemical reaction, and 

 unless new chemical laws are discovered it is useless to 

 attempt the employment of chemical agents. Epuration 

 must be confided to Dame Nature." 



Millions of dollars have been expended in France in 

 chemical experiments, all of which have been abandoned. 



