Drainage for Melbourne. 55 



in provincial towns serve for the sewage of the habitations of 

 about 1000 of the population. This is the result arrived at 

 after some years experience and investigation by the London 

 Board of Health. I assume that Melbourne and its suburbs 

 will, to a great extent, come within the description referred 

 to ; and taking its population at about 75,000, the length of 

 sewage to be provided would be about 150 miles. We have 

 then to arrive at some conclusions as to its cost. 



On referring to the table on the relative cost of supplying 

 earthenware drain pipes, and laying the same complete, as 

 given in the 179th page of the Report for 1852 of the London 

 Board of Health, it is found that the average cost of pipes, 

 and laying, in situations analagous in many respects to that 

 of our own city — the depth being nine feet below the surface, 

 and the diameter of the pipes varying from four inches to 

 twenty-one inches — was 8s. per yard, or .€700 per mile. Since 

 that date, improvements have been made in the manufacture 

 of the pipes, and the cost has also been reduced, but the alter- 

 ations have involved a little more labor in laying, so that 

 upon the whole the price may be fairly quoted as that which 

 probably obtains at home now. In order that I may not be 

 supposed to take too sanguine a view of the subject, I will 

 assume the cost here to be four times that at home, which 

 would bring the required outlay to £2800, but let us say 

 €3000 per mile. The total outlay, then, for the sewage 

 proper would be €450,000. As there would be other works 

 in connection with the final outlet, I will suppose their cost 

 to be €50,000, a sum nrach in excess of what would be 

 required, and that the total outlay would be €500,000 ; I 

 have then to show how that sum might be obtained, and how 

 it would ultimately be paid off. 



But before entering on this subject I may as well advert to 

 one or two other points in connection with the tubular system. 

 The first is a method of applying it, known as " back drain- 

 age," that is draining through back yards into lanes or bye- 

 ways, in preference to carrying the drains under houses to 

 main sewers in the streets. In many cases such a plan has a 

 very great advantage, both in economy and efficiency, but it 

 is not invariably applicable. One necessity to be kept in 

 mind is that of avoiding frequent angles and turns in drains 

 and therefore where much intricacy occurs, as in intersecting 

 courts and rights-of-way, back drainage is not equal to that 

 which admits of straight lines direct from the point of inlet 

 to the discharge into the sewer. This, however, does but 



