90 
strength, 1 in 60, 1 cubic foot of it will cost 4.3 cents, and it' the wood 
takes up 33 per cent, (by vol.) of the solution per cubic foot, it will re- 
quire J cubic foot of the weak solution, costing 4.3, ff{f=1.44 cents per 
cubic foot of lumber, or 5 cents per tie. Labor, at 810 per run, will cost 
$14,500 or 0.72 cent per cubic foot, or 2\ cents per tie. The total cost 
of this mode of preservation will, therefore, be: 
Per tie. 
Per cubic, 
foot. 
Interest on plant 
Material 
0. 69 
5. 04 
2. 52 
0.2 
1.4 
0.7 
Labor and fuel 
Total , 
8. 25 
2. 3 
d. Zinc Tannin. — If, in addition to chloride of zinc, glue and tannin 
are used, the cost of material is increased by 2.5 cents per tie, and the 
cost of labor and fuel J, or 0.5 cents per tie, making the total cost 11.25 
cents per tie, or 3.2 cents per cubic foot. 
e. Sulphate of Copper. — If a solution of sulphate of copper, 1 in 100, 
was to be injected by the same process, the change in cost would be in 
interest on plant and cost of material. As such works would cost about 
$60,000, the item of interest would be increased by one-half. As to 
cost for materials, sulphate of copper can now be bought at 7 cents per 
pound. Adding 99 pounds of water, 100 pounds, or 1.5 cubic feet of, 
the solution will cost 7 cents, or 1 cubic foot, 4.6 cents. 
Again, if one-third cubic foot of the solution be injected, the cost of 
material per cubic foot of wood will be 1.5 cents, and the cost per tie, 
5.25 cents. The total cost of preservation would then be : 
Per tie. 
Per cubic 
foot. 
1 Interest 
1.05 
5. 25 
2.5 
0.3 
1.5 
0.7 
1 Material • 
Total 
8. 80 
2.5 
/. Solutions of Chloride of Zinc, or Sulphate of Copper, injected by the 
Boucherie Process.— To treat 800 ties per day with zinc direct (pressure) 
by the Boucherie process, would require an investment of capital of 
about $5,000. The interest on this sum, at 20 per cent, (including re- 
pairs and renewal), would be $1,000, or on 250,000 ties, 0.4 cents per tie. 
The quantity and cost of the chloride of zinc and sulphate of copper 
would be the same as when treated by the modern process, plus one- 
quarter for loss of solution from treating round sticks and from leak- 
age. The labor would be 3 J cents per tie, and the total cost: 
