62 
THOMPSON YATES LABORATORIES REPORT 
Bed No. i has an area of 230 square yards, and No. la an area of 254 
square yards, with a capacity of 205 and 226 cubic yards respectively. The area of 
the two beds combined equals one-tenth acre. 
These beds commenced working on the 28th June, 1899, and were charged 
with crude sewage three times per 24 hours, each charge being allowed to remain 
in contact with the material in the bed for at least two hours. This rate of working 
was maintained up to the 25th October, 1899, without any period of absolute rest, 
with the exception of an occasional charge or two which were missed in times of 
heavy rainfall. On the 25th October, owing to the surface of Bed No. 1 becoming 
very foul, the charges were reduced to one per day, with the result that an 
improvement in the surface began at once to be noticeable. At the present time 
the charges on these beds are two per day, the increase taking place from the 13th 
December, 1899. 
On the 23rd January, 1900, a section of the bed was exposed and little if 
any sludge was found in the bottom ; but the whole of the material was uniformly 
and somewhat heavily coated with dark-coloured sewage matter, and worms were 
found in considerable numbers. The beds opened up sweet, and apparently without 
any bad smell whatever. Owing to the action of the weather upon the clay 
ballast, it was necessary on the 16th March, 1900, to remove about 3 inches from the 
surface and to replace it with coke. 
During the whole period the second contact bed No. la had worked well 
in conjunction with No. 1, as regards quantities, and has kept very clean on the 
surface. 
The following statement shows the capacity of the bed at the various times 
at which it has been tested by measurement : — 
Date 
Cubic feet 
Gallons 
*June 28th, 1899 
2,900 
l8,T20 
July 6th, „ 
2,500 
15,620 
October 6th, „ 
2,050 
I2,8lO 
November 29th, „ 
1,900 
11,870 
December 1 3th, ,, 
1,850 
I 1,560 
January 23rd, 1900 
1,760 
10,940 
February 23rd, „ 
1,700 
10,620 
March 19th, „ 
I,6oo 
10,000 
April 23rd, „ 
1,500 
9>37° 
*On this date, which was the first time on which the bed was charged, the material was dry. 
