t long. It is formed of iron plates 3/8ths of an inch thick, riveted
together. It is furnished with 181 brass tubes 1-7/8 inch diameter and 10
feet long, secured at the ends by ferules. The tube plate at the smoke box
end is 5/8ths of an inch thick, and the tube plates above the tubes are
tied together by eight iron rods 7/8ths of an inch thick, extending from
end to end of the boiler. The metal of the tubes is somewhat thicker at the
end next the fire, being 13 wire gauge at fire box end, and 14 wire gauge
at smoke box end. The rivets of the boiler are 3/4 inch diameter and 1-1/2
inch pitch. The plating of the ash pan is 5/16ths of an inch thick, and the
plating of the smoke box is 3/16ths of an inch thick.

659. _Q._--Will you describe the structure of the framework on which the
boiler and its attachments rest, and in which the wheels are set?

_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._--Th