190 REMARKS UPON THE DISPOSAL OF THE SEWAGE OF HOBART. 
statute law, the common sewer of the city; and it must be borne in 
mind, in considering the following facts, that it discharges itself into 
Sullivan’s Cove 600yds, further inland than the point of discharge into 
the tideway of the proposed new main sewer. On the mornings of the 
4th, 5th, and 6th of January, during dry weather, I gauged the water 
passing under Campbell-street bridge, and the mean of the gaugings 
gave a daily flow of 2,240,000 gallons, or 10,000 tons. As these gaugings 
were taken above the inflow of the Park-street rivulet, they may be 
safely taken as showing a mean dry weather flow not exceeding the 
reality. Samples of the water were carefully taken at the same time, 
These samples certainly did not err in aggravating the impurity of the 
water, as, on the contrary, large floating impurities, such as a dead 
rat and filth that is better left nameless, could not be taken into the 
sample bottles. If they could have been, the samples would assuredly 
have shown a larger quantity of ‘‘ organic matter in suspension.” For 
the purpose of ascertaining the effect of the discharge of the Rivulet 
into the Cove, samples of the Cove water were taken at 13 yards from 
the mouth of the Rivulet, 100 yards from its mouth, and at a point 150 
yards from the end of Elizabeth-street pier, and 450 yards from the 
mouth of the Rivulet. A sample was also taken in mid-stream of the 
Derwent, being half-way between Macquarie and Kangaroo Points. 
The following figures, all reduced to grains in the gallon of water, are 
the results of the Government Analyst’s examination of these samples, 
I am greatly indebted to him for all the trouble he took in the matter, 
For purposes of comparison there are added the means of a large number 
of analyses of samples of sewage collected for the Royal Commission 
on Rivers’ Pollution from more than thirty towns supplied with water 
closets; and of ordinary sea-water—the particular sample analysed— 
taken in the English Channel, but, as is well known, the composition 
of sea-water varies but little all over the world :— 
= oe S ick lone endl hic 
So x og — a) Et E ~ Nw . 
haloes) eel eee | Sa: loveereene 
bag) ais | see] s°e| 22 | 3 feb 
CONSTITUENTS. Gwe) OS | age | soa & a 18S 
£o8| RAE | ESE Eee) Be > |_He 
Sas|E.8| e288 /s42) oo | F [Soe 
290 1 3 Fo Ens a= S = wS 
Cg |es |S§s |S] 5A q |as's 
5 5 Baie So |x2 
Total nitrcgen in solution..| 0°61 0°20 0°06 0°02} 0°015 --- 5°41 
Chlorine in chlorides ,, 18°90 | 581°00 } 1029°00 | 1127-00 | 1127°00 | 1365°00 | 7°46 
Total solids in solution — ...| 62°33 | 1859°00 | 1948°00 | 2144°00 | 2151°00 | 2468°00 | 50°54 
Organic matterinsuspension| 8°10 1°00 0°40 0°50 0°60 _ 14°36 
Mineral matterinsuspension’ 11°33 1°80 0°90 0°90 1°10 — 16°93 
These figures, taken in connection with the relative volumes of the 
dry weather discharges from the Hobart Rivulet and the proposed 
Macquarie Point outfall, give the following results, the first column 
showing the daily quantity discharged from the Hobart Rivulet into the 
Cove, and the second column that proposed to be discharged from 
Macquarie Point into the tideway :— 
Of nitrogeninall formsin solution .. a! sf? -- 195lb. 6921b. 
Of chlorinein chlorides .. a BY, a2 me ie -. 6,048lb. 947lb. 
Of all matters in solution.. Ee og Be 7 ode .. 19,945lb. 6,4181b. 
Of organicmatterinsuspension.. af es, dv até .- 2,592lb. 1,823Ib. 
Of mineralmatterinsuspension.. #, 2a fs & -. 3,6251b. 2,1501b. 
Of all solid matters in solution and suspension... ae .. 26,162lb. 10,3911b. 
It will be noticed that the only matter that is greater in quantity at 
the Macquarie Point outlet than at the Hobart Rivulet is the nitrogen in 
solution. If the discharge were into a small basin of drinking water, 
