Four compressometers.

Two extensometers.

Four beam deformeters.

Four slip of rod apparatus.

Three Thatcher computing machines.

Two Draper recording thermometers.

One Bristol recording thermometer.

One muffle furnace.

Two gas furnaces.

One gas generator for chemical laboratory.

One Buffalo portable forge.

Two lever jacks.

One Lodge & Shipley machine lathe.

One 70-horsepower horizontal tubular boiler.

One 74-horsepower Habercorn slide-valve engine.

One Worthington fire pump.

One Westinghouse dynamo.

In addition to the above equipment all the divisions of the laboratories have a complete equipment of smaller apparatus, and facilities for making the tests covered by the investigations.

ACKNOWLEDGMENT OF DONATIONS.

The extent and importance of the investigations of structural materials being conducted by the United States Geological Survey are such that in order to procure the needed information in a reasonable time, it is necessary to make the available appropriations cover as much work as possible. These appropriations are relatively small in comparison with the amount of work to be done, and it is extremely desirable that all persons interested in this work should accord it their hearty support as far as possible. The results of these investigations will be of great value not only to the Government, but to the public at large, especially engineers, architects, contractors, manufacturers, and all others who manufacture or use structural materials. The help which has been received up to the present time has made it possible to devote to the investigations a large amount of money that otherwise would have been spent in defraying transportation charges for materials and men, and for purchasing the materials with which to conduct the investigations. In most cases it has been simply necessary to make known the needs of these laboratories for materials or transportation; in a few cases material has been especially solicited, and in almost every case the reply has been a generous compliance with the request.

Railroads have aided in the work by transporting the materials and the employees of the laboratories free of charge. Special acknowledgments are made to those lines and to certain Portland cement manufacturers, collectively and individually; also to the Municipal Engineering and Contracting Company, the Hyd Engineering Company, the Concrete Block Machine Man

Association, the Underwriters' Laboratories of Chicago, the Illinois Steel Company, the Carnegie Steel Company, and the Ingersoll-Rand Drill Company.

Acknowledgment is due the Union Sand and Material Company, of St. Louis, Mo., for donations of material as well as for courtesies extended and for service in delivering material by teams for use in these laboratories.

The tests that are being made require large quantities of cement, sand, gravel, stone, and steel, and up to the present time these have been contributed generously and promptly upon request. For donations of Portland cement acknowledgments are made to the following companies:

Alpha Portland Cement Co., Easton, Pa.
American Cement Co., Egypt, Pa.
Atlas Portland Cement Co., Hannibal,
Mo.

Peerless Portland Cement Co., Union
City, Mich.

Penn Allen Portland Cement Co., Bath,
Pa.

Bonneville Portland Cement Co., Sieg- Pennsylvania Cement Co., Bath, Pa.
fried, Pa.

Phoenix Cement Co., Nazareth, Pa. Chicago Portland Cement Co., Oglesby, Sandusky Portland Cement Co., Syra

Coplay Cement Manufacturing Co., Cop- St. Louis Portland Cement Co., St. Louis, lay, Pa.

Dexter Portland Cement Co., Nazareth,

Pa.

Edison Portland Cement Co., Stewartsville, N. J.

Mo.
Universal Portland Cement Co., Chicago,
Ill.

Virginia Portland Cement Co., Fordwick,
Va.

German-American Portland Cement Co., Vulcanite Portland Cement Co., Vulcan

For contributions of steel bars acknowledgments are made to the Illinois Steel Company and to the Carnegie Steel Company. For donations of sand, gravel, and crushed stone in carload lots acknowledgments are made to the following:

Carmichael, Wm. R., Williamsport, Ind.
Casper-Stolle Construction Co., East St.
Louis, Ill.

Chicago Crushed Stone Co., Chicago, Ill.
East St. Louis Stone Co., East St. Louis,
Ill.

Fruin-Bambrick Construction Co., St.
Louis, Mo.

Grafton Quarry Co., Grafton, Ill.

McLaughlin-Mateer Co., Kankakee, Ill.
Ozark Red Granite Co., St. Louis, Mo.
Reliance Quarry Co., Alton, Ill.
Rickey, C. A., Louisville, Nebr.
Schneider Granite Co., St. Louis, Mo.
Union Sand and Material Co., St. Louis,
Mo.

United Railways of St. Louis.

For courtesies extended and facilities afforded in investigating the various deposits of sand, stone, and gravel, forming a part of the field work of these laboratories, acknowledgments are made to the following:

American Sand and Gravel Co., Chicago, Lauer, Jacob, St. Paul, Minn.

Granby Zinc and Mining Co., Joplin, Mo. St. Joseph Lead Co., Hoffman, Mo.

St. Joseph Street Construction Co., St.
Joseph, Mo.

Samuels & Holmes, Kansas City, Mo.
Scullin-Gallagher Iron and Steel Co.,
St. Louis, Mo.

Houston and Texas Central Railroad, Sheehan, J. P., Austin, Tex.

PROGRAMME FOR

INVESTIGATION OF CONCRETE AND REIN-
FORCED CONCRETE,

ORIGIN OF THE PLAN.

In October, 1904, the joint committee, in session at the Louisiana Purchase Exposition, St. Louis, Mo., adopted a programme of the tests necessary to procure the information desired in the preparation of a report on concrete and reinforced concrete, together with suggestions for putting the same into effect. The plan proposed that the subcommittee on tests should arrange for the cooperation of the joint committee with those schools of technology having adequate facilities for making the tests desired, and also arrange to supervise these tests so as to insure the proper accuracy and correlation of work. Materials of uniform and satisfactory quality were to be furnished to the different institutions, and methods of testing were to be outlined so as to standardize them as far as practicable. The inspection of the preparation of the test pieces and testing of the same by an experienced assistant was to be maintained, in order that the sources of error arising from the investigation of closely related problems at scattered laboratories might be reduced to a minimum. Funds to defray the cost of the material and the expense of efficient inspection were to be raised by a subcommittee on ways and means.

In response to an invitation issued by the subcommittee on tests in behalf of the joint committee, the following technical institutions expressed a willingness to cooperate in the work: Case School of Applied Science, Columbia University, Cornell University, Harvard University, Massachusetts Institute of Technology, Ohio State University, Purdue University, State University of Iowa, University of Illinois, University of Minnesota, University of Pennsylvania, and University of Wisconsin. The investigations assigned by the subcommittee on tests were conducted at these institutions during the same college year (1904-5) by advanced students or members of the instruction staff. Since arrangements for investigative work by students in nearly all such institutions necessitate the completion of any series of tests by at least the last of May of each year, the time available proved insufficient for making needed arrangements and providing materials sufficiently in advance to permit the completion of the requisite tests. This rendered impossible the thorough organization that was desired in the first year's work.

DETAILS OF THE PLAN.

I. EXAMINATION AND CLASSIFICATION OF CONSTITUENT MATERIALS.

A. Examination of deposit.-Sands, gravels, stones, gravel and stone screenings (4-inch screen), slags, cinders, etc., are to be collected by a special representative of the testing laboratory sent out for that purpose. The deposit from which the samples are collected is to be examined to determine the extent and natur of the material.

B. Physical tests in the laboratory. The laboratory tests are to include the examinations and determinations indicated below:

1. Mineralogical examination.

2. Specific gravity.

3. Weight per cubic foot.

4. Sifting (granulometric composition).

5. Percentage of silt and character of

same.

6. Percentage of voids.

7. Character of stone as to percentage of absorption, porosity, permeability, compressive strength, and behavior under treatment.

C. Chemical analysis.—Analyses are to be made to determine the composition and character of the stone, silt, etc., used in tests.

II. TESTS AND CLASSIFICATION OF MORTARS MADE WITH TYPICAL PORTLAND CEMENT AND SAND, GRAVEL, AND STONE SCREENINGS (-INCH SCREEN).

A. Proportions and conditions.-Proportions to be stated by weight and volume. The unit of volume for cement is 100 pounds per cubic foot. The typical Portland cement is to be prepared by thoroughly mixing a number of brands, each of which must meet the following requirements:

Specific gravity, not less than 3.10.

Fineness, residue not more than 8 per cent on No. 100 nor 25 per cent on No. 200 sieve.

Time of setting: Initial set, not less than 30 minutes; hard set, not less than 1 hour nor more than 10 hours.

Constancy of volume: Pats of neat cement 3 inches in diameter, one-half inch thick at center, tapering to a thin edge, shall be kept in moist air for a period of 24 hours. A pat is kept in air at normal temperature and observed at intervals for at least 28 days. Another pat is kept in water maintained as near 70° F. as practicable and observed at intervals for at least 28 days. A third pat is exposed in an atmosphere of steam above boiling water in a loosely closed vessel for 5 hours. These pats must remain firm and hard and show no signs of distortion, checking, cracking, or disfiguration.

The cement shall not contain more than 1.75 per cent anhydrous sulphuric acid nor more than 4 per cent magnesium oxide.

A test of the neat cement must be made with each mortar series for comparison of the quality of the typical Portland cement.

B. Physical tests in laboratory.—The laboratory tests include the following determinations, those designated as items 1 to 10 being each made at the ages of 7, 28, 90, 180, and 360 days:

1. Tensile strength with one part cement to varying percentages of material.

2. Compressive strength with one part cement to varying percentages of material. 3. Transverse strength with one part cement to varying percentages of material. 4. Shearing strength with one part cement to varying percentages of material.

5. Tensile strength with cement, material sifted to one size.

6. Compressive strength with cement, material sifted to one size.

7. Transverse strength with cement, material sifted to one size.