52 Suggestions for a System of 



These being ascertained, the size of the sewers became a 

 mere matter of calculation. Undoubtedly in London, and in 

 some of the larger towns, the passage of storm waters supplied 

 another item for consideration. But, as before shown, surface 

 drainage and house sewage should be kept distinct whenever 

 this can be effected. In this country, where long dry seasons 

 are succeeded by heavy storms, it would appear to me to be 

 exceedingly absurd to attempt the combination of both in 

 one system. But while the principal utility of such sudden 

 irruptions of water is to " flush" the sewers ; in our case we 

 are rendered independent of this use of storm waters, by the 

 command which we possess in the powerful and continuous 

 supply of the Yan Yean. For these reasons, I would suggest 

 that we may confine our attention to the three primary 

 requirements as already stated. 



Before, however, proceeding further, I may allude to the ob- 

 jections that have been made to the tubular system of drainage 

 as compared with that by brick sewers, which may be thus 

 stated : — * 



1. Danger of breakage from weight of superincumbent 

 earth, &c. 



This objection is plausible, but unsound. Undoubtedly, 

 when stoneware drain pipes are placed within six or twelve 

 inches of a common road, damage may be reasonably ex- 

 pected, but in no instance has experience shown that such 

 pipes, placed in similar situations to brick sewers and pro- 

 perly bedded, have failed to bear all the weight imposed upon 

 them. 



2. That the sedimentary deposit quickly becomes a complete 

 plug. 



To this it is replied that experience has demonstrated that, 

 with the ordinary proportion of water in the sullage, when 

 the pipes are properly laid, no deposit can or does take 

 place. 



3. The liability of stoppage from substances that would 

 find their way in the larger channels. 



This may be admitted, if it can be shown that large sub- 

 stances can find their way into small drains. With ordinary 

 care, the admission of foreign matter can be prevented; and 

 for tbe removal of all, except bodies as large as the drains 



* I acknowledge here the value of a very fair Summary in the Engineer's 

 Pocket Book for 1858. 



