Kyanized Spruce post, 6" x 8", in Reservoir fence, Lynde's Hill, Lowell, Mass., since 1850. Dug up and photographed in 1891.

the sides of the posts, at and near the ground. The fence has been whitewashed with lime a number of times since it was built, and this undoubtedly has had a tendency to preserve the part above ground, independent from the kyanizing process. This example is as good a one as can be found in this vicinity, and clearly demonstrates the economy of kyanizing spruce timber that is to be placed in situations which expose it to decay.

Spruce posts may last from six to eight years, if placed in the ground in their natural state, depending much upon their condition. If full of sap, they would decay very quickly; but if well seasoned before they are placed in the ground, they would last several years longer. In the case of the reservoir fence above mentioned, the kyanized posts lasted thirty-five years before any repairs were made. The fence is now in good condition, and will wear for a number of years more.

Plate VII. is a view of one of the spruce posts in the same. reservoir fence, taken up very recently at the point indicated in Plate VI., where the three men are at work. It is a remarkably good specimen of kyanized spruce, which after forty-one years of service remains apparently as sound and good as the day it was put in the ground. It is exceptional, however, as most of the posts in the reservoir fence are more or less decayed near the ground line, although the parts above and below the surface are apparently quite sound.

The cost of kyanizing depends mainly upon the cost of corrosive sublimate, which is one of the important products made from mercury. The present charge for kyanizing at Lowell is eight dollars per thousand feet board measure, which gives a small profit, and enables the company to keep the works and railroad tracks leading to them in good running order. The amount of lumber treated at Lowell, including what has been done for outside parties, averaged about 750,000 feet board measure per annum for the past six years, and represents about one-half of the capacity of the works.

Powers & Weightman, manufacturing chemists of Philadelphia and large manufacturers of corrosive sublimate, in a recent interesting communication, give some facts which are here quoted:

"Quicksilver is largely produced in Europe and also in this country. There are various causes for the fluctuation in the price of quicksilver. The Spanish product is controlled by the Rothschilds, who frequently have opportunities for manipulating the market in their own interests; then, again, the price is affected by the law of supply and demand, although there never is an absolute scarcity. The prices in this country are governed very largely by the prices ruling on the other side. The present rate of duty on quicksilver is ten cents per pound on what is imported, and is about double what it was prior to the passage of the present law."

The prices paid for corrosive sublimate at Lowell, when purchased by the ton, for the past few years, are as follows: 1876, fifty-eight cents per pound; 1880, forty-three cents; 1885, fifty-one cents; 1886, fifty-seven cents; 1888, sixtyeight cents; 1890, seventy-four cents; 1891, sixty-six cents. In Lowell it is found that lumber takes up from three to five pounds of corrosive sublimate per thousand feet board measure, depending upon its condition; and corrosive sublimate, being soluble in water, will penetrate farther in green lumber that is full of moisture than in dry lumber, although lumber in the green state will not take up as much of it as when it is dry.

Two vats or tanks are used at Lowell for kyanizing. The larger one measures fifty-two feet nine inches long, eight feet five inches wide and four feet six inches deep. It will hold from twelve to fifteen thousand feet board measure of timber, depending upon the dimensions, and it is of ample size to hold an ordinary car load of timber. This tank was constructed in 1887, of brick, and, to prevent any leakage, all of the bricks in the inside courses of the walls and floor were first dipped and then laid in pitch made from coal tar at a temperature of about 300° F.

Corrosive sublimate is an acrid poison, and many persons have predicted that the health of workmen engaged at and about the tanks would be injured by it. Such has not been the experience of the workmen at Lowell. Since 1848, when kyanizing was first introduced there, not a single case of serious injury from poisoning is reported, but on the contrary, workmen who have been employed for years believe that certain benefits are derived from it, such as the rapid healing of sores, prevention of fevers, and the healing and strengthening of weak eyes.

A report on the preservation of timber was made by a special committee of the American Society of Civil Engineers, and published in 1885. It covers five years of investigation, and embraces a clear and comprehensive statement of all modern methods adopted in various countries.

The indications are that no single process seems to be adapted to every situation where timber is exposed to decay, and that failures sometimes occur. Timber has been known to decay in a comparatively short time after treatment, and the cause of it cannot always be found. Manufacturers of leather experience the same trouble, and lose many hides from failure in the treatment, which cannot readily be accounted for. Timber treated with salts should not be placed in very wet situations, because the salts are easily soluble in water, and are liable to be washed out. The oils are much less soluble, but the cost of treatment is greater.

Whether or not our railroad corporations comply with the rules of economy in using wood ties in their natural state, which usually last from six to eight years, rather than, by proper methods of treatment, preserving them to last from two to four times that length of time, is a matter that has received and is receiving earnest consideration. The steadily advancing prices and the growing scarcity of timber will soon force the larg consumers to resort to methods of preservation from decay a much greater extent than is done at the present day.