359 
I have also collected the following particulars for your 
Ladyship's information. 
1. The filter is placed at the outlet of a sewer on the 
Hartwell Road, and intercepts the sewage from a section 
of the town containing about 2000 Inhabitants. 
2. The Tank is constructed of brickwork, set in a com- 
position of equal parts of Roman cement and common lime. 
The filter boards are of red pine, and perforated with holes an 
inch in diameter. The filter is 10 feet long by 6 feet wide, 
giving an area of 60 feet, and the space between the upper 
and lower boards, forming the filter, is 2 feet 6 inches. 
3. The entire cost of the tank and the filter was £27, 
and it was completed within 14 days. 
4. The filtering medium is peat charcoal, which abstracts 
all offensive and colouring matter, and immediately the 
sewage is withdrawn from the filter, it becomes a dry, 
portable, and inodorous manure, fit for packing in barrels or 
sacks, and capable of being transported by any public con- 
veyance. 
5. The filter beds hold 30 cwt. of peat charcoal, which 
requires changing every four weeks, and when removed, it is 
found to have taken up its own weight of fertilising matter. 
6. The present price of peat charcoal ranges from 50s. 
to 60s. per ton, but, by proper arrangements, it can be 
manufactured for 20s. per ton. 
7. The average results of a year's working of the Ayles- 
bury tank appear thus : — 
£. s. d. £. s. d. 
CR. By sale of 39 Tons of Peat Charcoal ) i tt n n 
Manure, at 60s ( 1 1 ' U U 
DR. To Cost of 19| Tons of Peat Charcoal > 43 ] 5 0 
tit t50s * •••••••••»••«••••••••••••••#•••••••• ) 
Labour, emptying and refilling Tank 5 4 0 
Cartage, fcc 6 10 0 
Repairs, Interest, &c 2 14 0 
63 3 0 
One Year's Profit £53 17 0* 
* At a recent discussion at the Society of Arts, consequent on the reading of 
a paper by Mr. Longraaid, on charcoal, the Rev. J. B. Read remarked, " that 
