105 
while t be second was left in its natural state, ami both placed in the 
ground under the same conditions. At the end of three years the 
painted specimen was found to exhibit no signs of decay, but the un- 
padded one was in a rotten state. 
The district surveyor of buildings inclines very favorably to the use 
of carbolineum on buildings in the water, and on sluice-gates, dam- 
barriers, piles, posts, especially when the wood is kept wet or dry, or 
by turns wet and dry. 
It is found that carbolineum is cheaper than the semi-fluid tar. For 
an area of six square meters one kilogram of carbolineum is ordina- 
rily used; and its superiority over tar is shown by the fact that even 
the largest manufacturers, where tar is a by-product, and the use of 
which costs nothing, are coming to use carbolineum. 
It is best and most advantageous to paint with hot carbolineum, for 
in this stale it is more fluid than when unboiled, and for this reason 
penetrates into all cracks and openings, at the same time dissolving any 
resin or oil present ; it also disinfects more energetically in a warm state 
than in a cold one. In warm weather, and on wood when the surface 
is not buried in the earth, it is necessary to give a thicker coating of 
the indicated oil, especially as it can be repeated after a while. Wood 
that is not completely air-dried must always be treated with hot car- 
bolineum. All the wooden posts of bridges that are exposed to changes 
of wet and dry, as well as their gravel-covered layer of planks, are 
painted with two coats of hot carbolineum. All knotty wood surfaces 
must be very carefully treated, applying only so much as will be readily 
absorbed. The knotty surfaces of wood being the places where the 
ducts open, these are thus the very localities where the decay and de- 
struction from lower organisms begin, and it is on this account that they 
must receive special protection. One kilogram of carbolineum (which 
comes in casks of about two hundred kilos, each), costs 0.3 marks=7 
cents. 
ANNUAL CHARGES FOR TIES. 
By B. E. Fernow. 
There appears to have been some difficulty experienced by engineers 
in coming t o a conclusion as to how different processes ought to be com- 
pared in regard to the annual charge, which must vary according to the 
difference of the initial cost of the ties and the difference in the number 
of years that they will last, and, in addition, to the frequency at which 
the expense of renewal recurs. The difficulty, it seems, need not exist 
at all, and can be removed by the application of simple mathematical 
formulas and mathematical deductions, and put into a form which will al- 
low a ready comparison of the annual charge for ties of different prices 
and varying conditions. For this purpose the following tables have 
