2 Foremen, at $900 each | 1,800.00
1 Timekeeper | 900.00
3 Watchmen and Gauge Tenders, at $900 each | 2,700.00
1 Machinist | 1,140.00
1 Blacksmith | 900.00
1 Storekeeper | 900.00
1 Painter | 900.00
1 Mechanic | 900.00
1 Electrician | 900.00
4 Skilled Laborers at $600 each | 2,400.00
1 Watchman and Special Officer | 900.00
1 Recorder | 720.00
27 Laborers, at $1.50 per day for 300 days | 12,150.00
3 Teams, at $2.00 per day for 200 days | 1,200.00
Laboratory and office supplies | 2,700.00
Filter supplies, tools, hose, repair of |
roads, parks, shrubs, etc. | 8,820.00
Pumping station supplies, oil, waste, |
packing, repairs, etc. | 3,570.00
3,600 tons of coal, at $3.15 per ton | 11,340.00
Charges in U. S. Engineer Office, labor | 2,900.00
Charges in U. S. Engineer Office, materials | 400.00
--------------------------------------------------------+-----------
Total | $82,000.00
========================================================+===========

The results obtained from operating the filters being such as to
justify the conclusions in the report referred to, an experimental
plant was constructed for the purpose of studying the efficiency of
various methods of preliminary treatment of the water. This plant
consisted of three cylindrical concrete filter tanks, each 10 ft. in
diameter. These tanks were filled with the layers of gravel and sand
necessary to make them represent as accurately as possible the large
slow sand units of the main filtration plant. Means were also
provided for giving a preliminary treatment to the water supplying
each of these experimental slow sand filters. In two cases, the
preliminary treatment was rapid filtrati