[Illustration: PLATE XIII. Fig. 1.--Testing Beam in 200,000-Lb. Machine. Fig. 2.--Fire Test of Panel.] This machine is a large hydraulic press, with an adjustable head, and a weighing system for recording the loading developed by a triple-plunger pump. It has a maximum clearance of 65 ft. between heads; the clearance in the machine is a trifle more than 6 ft. between screws, and the heads are 6 ft. square. The machine consists of a base containing the main cylinder, with a sectional area of 2,000 sq. in., upon which rests the lower platform or head, which is provided with a ball-and-socket bearing. The upper head is adjustable over four vertical screws, 13½ in. in diameter and 72 ft. 2 in. long, by a system of gearing operating four nuts with ball-bearings upon which the head rests. The shafting operating this mechanism is connected with a variable-speed motor which actuates the triple-plunger pump supplying the pressure to the main cylinder (Fig. 4). The weighing device consists of a set of standard Olsen levers for weighing one-eightieth of the total load on the main cylinder. This reduction is effected through the medium of a piston and a diaphragm. The main cylinder has a diameter of 50 in., and the smaller one, a diameter of 5-9/16 in. The weighing beam is balanced by an automatically-operated poise weight, and is provided with a device for applying successive counterweights of 1,000,000 lb. each. Each division on the dial is equivalent to a 100-lb. load, and smaller subdivisions are made possible by an additional needle-beam. The power is applied by a 15-h.p., 220-volt, variable-speed motor operating a triple-plunger pump, the gearing operating the upper head being driven by the same motor. The extreme length of the main screws necessitates splicing, which is accomplished as follows: In the center of the screws, at the splice, is a 3-in. threaded pin for centering the upper and lower screws; this splice is strengthened by sleeve nuts, split to facilitate their removal whenever it is necessary to lower the upper head; after the head has passed the splice, the sleeve nuts are replaced. In order to maintain a constant load, a needle-valve has been provided, which, when the pump is operated at its lowest speed, will allow a sufficient quantity of oil to flow into the main cylinder to equalize whatever leakage there may be. The main cylinder has a vertical movement of 24 in. The speed of the machine, for the purpose of adjustment, using the gearing attached to the upper head, is 10 in. per min. The speed for applying loads, controlled by the variable-speed motor driving the pump, varies from a minimum of at least 1/60 in. per min. to a maximum of at least ½ in. per min. The machine has a guaranteed accuracy of at least one-third of 1%, for any load of more than 100,000 lb., up to its capacity. [Illustration: Fig. 4. PLAN AND ELEVATION OF 10,000,000-LB. VERTICAL COMPRESSION TESTING MACHINE]