The castings for the base and the top head weigh approximately 48,000 lb. each. Each main screw weighs more than 40,000 lb., the lower platform weighing about 25,000 lb., and the main cylinder, 16,000 lb. The top of the machine will be about 70 ft. above the top of the floor, and the concrete foundation, upon which it rests, is about 8 ft. below the floor line. [Illustration: PLATE XIV. 10,000,000-Lb. Testing Machine.] _Concrete and Cement Investigations._--The investigations relating to concrete include the examination of the deposits of sand, gravel, stone, etc., in the field, the collection of representative samples, and the shipment of these samples to the laboratory for analysis and test. These tests are conducted in connection with the investigation of cement mortars, made from a typical Portland cement 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 to exceed 8% on No. 100, nor 25% on No. 200 sieve; Time of setting: Initial set, not less than 30 min.; hard set, not less than 1 hour, nor more than 10 hours. Tensile strength: Requirements applying to neat cement and to 1 part cement with 3 parts standard sand: -------------------------------+--------------+---------- | Neat cement. | 1:3 Mix. Time specification. | Pounds. | Pounds. -------------------------------+--------------+---------- 24 hours in moist air | 175 | ... 7 days (1 day in moist air, | 500 | 175 6 days in water) | | 28 days (1 day in moist air, | 600 | 250 27 days in water) | | -------------------------------+--------------+---------- Constancy of volume: Pats of neat cement, 3 in. in diameter, ½ in. 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° Fahr. as practicable, and is 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% of anhydrous sulphuric acid, nor more than 4% of 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. The constituent materials are subjected to the following examination and determinations, and, in addition, are analyzed to determine the composition and character of the stone, sand, etc.: 1.--Mineralogical examination, 2.--Specific gravity, 3.--Weight, per cubic foot,