A.—­The framework or framing consists of a rectangular structure of plate iron circumscribing the boiler, with projecting lugs or arms for the reception of the axles of the wheels.  In this engine the sides of the rectangle are double, or, as far as regards the sides, there are virtually two framings, one for the reception of the driving axles, and the other for the reception of the axles not connected with the engine.  The whole of the parts of the outer and inner framings are connected together by knees at the corners, and the double sides are elsewhere connected by intervening brackets and stays, so as to constitute the whole into one rigid structure.  The whole of the plating of the inside frame is 3/4 inch thick and 9 inches deep.  The plating of the outside frame is of the same thickness and depth at the fore part, until it reaches abaft the position of the cylinders and guides, where it reduces to 1/2 inch thick.  The axle guard of the leading wheels is formed of 3/4 plate bolted to the frame with angle iron guides.  The axle guards of the trailing wheels are formed of two 1/2 inch plates, with cast iron blocks between them to serve as guides.  The ends of the rectangular frame are formed of plates 3/4 thick, and at the front end there is a buffer beam of oak 4-1/2 inches thick and 15 inches deep.  The draw bolt is 2 inches diameter.  There are two strong stays on each side, joining the barrel of the boiler to the inside framing, and one angle iron on each side joining the bottom of the smoke box to the inside framing.

660. Q.—­Of what construction are the wheels?

A.—­The wheels and axles are of wrought iron, and the tires of the wheels are of steel.  The driving wheels are 6 feet 6-1/2 inches in diameter, and the diameter of crank pin is 3-1/2 inches.  The diameter of the smaller wheels is 48-1/2 inches.  The axle boxes are of cast iron with bushes of Fenton’s metal, and the leading axle has four bearings.  The springs are formed of steel plates, 3 feet long, 4 inches broad, and 1\2 inch thick.  The axle of the driving wheel has two eccentrics, forged solid upon it, for working the pumps.

661. Q.—­Will you specify the dimensions of the principal parts of the engine?

A.—­Each of the cylinders which is 14-1/4 inches diameter, has the valve casing cast upon it.  The steam ports are 13 inches long and 1-5/8 inches broad, and the exhaust port is 2-1/2 inches broad.  The travel of the valve is 4-1/8 inches, the lap 1 inch, and the lead 1/4 inch.  The piston is 4 inches thick:  its body is formed of brass with a cover of cast iron, and between the body and the cover two flanges, forged on the piston rod, are introduced to communicate the push and pull of the piston to the rod.  The piston rod is of iron, 2-1/2 inches diameter.  The guide bars for guiding the top of the piston rod are of steel, 4 inches broad, fixed to rib iron bearers, with hard wood 1/4 of an inch thick, interposed.  The connecting