S!) 
total Dumber of rans per annum would be 240 (with 2 cylinders); the 
□umber of cubic feet of timber treated per annum, 350,000; the labor 
and fuel per run, $60, and the total cost of treating 1 cubic loot of tim- 
ber: interest on plant, ^ -J^ =2.3 cents per cubic foot; material (20 
pounds at 0.8 cents), L6.0 cents; labor and fuel, L3 cents • total, 22.0 
cents, or about $19 per 1,000 feet B. M. 
b. Kyanizing. — If the impregnation is to be carried out in the ordi- 
nary way, by steeping, and if the works are to be of sufficient capacity 
to treat 250,000 ties per annum, or, say, 800 ties, equal to 2,800 cubic feet 
of timber per day, and if the steeping is to be continued for 7 days, 
there must be tank room for, say, 20,000 cubic feet of timber. Allow- 
ing 1.3 cubic feet of tank-room for 1 cubic loot of timber, the total 
capacity of the tanks required will be 20,000 cubic feet, and if tanks 50 
feet long, 7.5 feet wide, 5 feet deep are used, about 14 tanks will be re- 
quired. 
The plant would cost probably $10,000, and on 250,000 ties the charge 
for interest on plant would be (at 15 per cent, in repair and renewal) 
0.0 cents per tie. 
If 0.0G pound of bichloride of mercury is used per cubic foot, or 0.21 
pound per tie (of 3.5 cubic feet), and the sublimate costs 50 cents per 
pound, the cost of material is 50x0.21=10.5 cents per tie. Labor and 
fuel would be about 3.5 cents per tie, and the total cost of Kyanizing: 
Per tie. 
Per cnbic 
foot. 
Interest on capital 
Material 
Labor and fuel 
Total 
Cents. 
0.G 
10.5 
3.5 
Cents. 
0. 17 
3.00 
1.00 
14. G 
4.17 
Bridge timber would have to be steeped during two weeks, instead of 
one, and as, therefore, only half so much lumber could be treated as in 
the case of ties, the interest on capital would be doubled, the cost of 
material and labor remaining the same; the cost of treatment per cubic 
foot would, therefore, be increased only about one twenty-fifth, and 
would be 4.34 cents per cubic foot. 
c. Chloride of Zinc. — If ties are to be impregnated by steaming, vacu- 
um, and pressure, the cost of plant required (in connection with two 
injecting reservoirs) is about $40,000. Assuming the time used for one 
run at 10 hours, GO runs could be made per month with each cylinder, 
or 120 runs with the two cylinders, or 1,450 runs per annum. Taking 
400 ties per run, the total number of ties which could be treated in a year 
would be 580,000, equal to, say, 2,000,000 cubic feet of timber. Allow- 
ing 10 per cent, interest on cost of plant will give $4,000,pr JfJJ-JS =0.69 
per tie, or 0.2 per cubic foot. The cost of concentrated chloride of zinc 
(specific gravity 1.5) is about $2.60 per cubic foot. If the solution has a 
