Track put up on ballast washed and screened as clean as possible. Material under 4-inch not more than 7 per
cent. This for test to determine whether it would not be possible to reduce the percentage of sand as recom-
mended in A. R. E. A. Manual. One thousand feet of track was lifted twelve inches at Culvert No. 495 (shown in back-
ground) September, 1915 Cost of
maintenance since that time to Noven ber 15. 1916, $500 total Southbound side look-
LIK south to Guinea Station. House in which General Stonewall Jackson died shown in left background,

Inquiry has been made of State Highway Departments and other sources for a description of an "accelerated weathering test," and the following letter is of interest:

STATE HIGHWAY DEPARTMENT

Harrisburg, Pa., Nov 22, 1916.

Mr. D. L. Sommerville, Superintendent, St. Lawrence Division, The New York Central Railroad Company, Watertown, N. Y.

Dear Sir:

In reference to yours of the 10th inst., relative to specifications for stone for ballast, would say that I know of no accelerated weathering test which has been developed by anyone t› be applied to natural stone, though I believe that high temperature and freezing tests are commonly made on building materials.

I would state that the nearest developments along this line, which would probably cover the majority of conditions met with in stone, are as follows:

(a) Absorption Test. Since soft and particularly porous stones always show higher results in this test than the dense varieties, this could be supplemented by a freezing test, placing the specimen from the absorption test, containing the water absorbed, into a vessel which would be surrounded by a freezing mixture of ice and a suitable salt. The general run of results of absorption tests can be obtained from the Office of Public Roads' records.

(b) Slaking Test. This test was formerly used by the Office of Public Roads to distinguish slaking and non-slaking clays on sand-clay work, and I believe it was also used on briquettes made up for the cementation test on crushed stone. We have taken a sample of argillaceous limestone from Washington County, used in 1915, which was recently reported to me by Mr. Tebbs as having disintegrated in a concrete curb on Application No. 132, Washington County, and found that briquettes made up for the cementation test, and afterwards dried out in the usual way, slaked down in a few minutes in water.

To summarize the above statements, I think that an absorption-freezing test combined would disclose porous sandstone or any other stone which had become porous through weathering, and that a slaking test would disclose shales or shaley limestone which, although hard when first taken from the quarry, break down on exposure to the weather.

Very truly yours,

(Signed) W. D. UHLER. Chief Engineer.

CONCLUSION.

Your Committee recommends adding a "weathering test" to the approved tests of stone for ballast and will make further inquiry and investigation in the hope of finding an "accelerated weathering test" and make a definite recommendation to the Association in its next annual report.

The following letter from the former Chief Engineer of the Baltimore & Ohio Railroad (F. L. Stuart) in regard to the use of the physical test of stone for ballast, is of interest and is one of the first cases where these tests have been used in practice: