XXII. 



J. G. S. PURVIS. 



effected by the septic tank installation at Rookwood Asylum. 

 The results are based upon the chemical analyses of average 

 samples of crude sewage, and of average samples of effluents, each 

 taken at the same hour on the same day. 



Dates. 



By the amount of oxygen 

 consumed in four hours. 



80 

 85 

 75 

 Mean 82 



By the difference in the albu- 

 minoid ammonias in both 

 effluent and crude. 



24th February, 1900 

 16th March, 1900 ... 

 25th April, 1900 



S3 

 83 

 89 



Finally, the writer's object in placing this short paper before 

 this Society is rather to promote discussion than to impart know- 

 ledge; also in the hope that the lay mind will be solaced by the 

 fact that the Metropolitan Board are fully alive to the importance 

 of this matter, and that a proper solution of the sewage problem, 

 such as they are endeavouring to obtain is the best means of con- 

 serving the public health. 



