BRICK EOADS. 35 
but where the total quantity exceeds 100,000. the number of samples tested 
may be fewer than 1 per 10,000, provided that they shall be distributed as 
uniformly as practicable over the entire lot. 
Item 4. Shipment of samples. — Samples which must be transported long 
distances by freight or express must be carefully put up in packages holding 
not more than 12 brick each. When more than six brick are shipped in one 
package, it must be so arranged as to carry two parallel rows of brick side 
by side, and these rows must be separated by a partition. In event of some 
of the brick being cracked or broken in transit, the sample shall be disqualified 
if there are not remaining 10 sound undamaged brick. 
Item 5. Storage and care of samples. — Samples must be carefully handled 
to avoid breakage or injury. They must be kept dry so far as practicable. If 
wet when received, or known to have been immersed or subjected to recent 
prolonged wetting, they shall be dried for at least six hours in a temperature 
of 100° F. before testing. 
THE CONSTRUCTION OF THE EATTLEE. 
Item 6. The machine shall be of good mechanical construction, self-con- 
tained, and shall conform to the following details of materials and dimensions, 
and shall consist of barrel, frame, and driving mechanism as herein described. 
Accompanying these specifications is a complete drawing (PI. XII) of a 
rattler which will meet the requirements, and to which reference should be 
made. 
Item 7. The barrel. — The barrel of the machine shall be made up of the 
heads and head liners and staves and stave liners. 
The heads may be cast in one piece with the trunnions, which shall be 2* 
inches in diameter and shall have a bearing 6 inches in length, or they may 
be cast with heavy hubs, which shall be bored out for 2iVinch shafts, and shall 
be keyseated for two keys, each | inch by f inch and spaced 90° apart. The 
shaft shall be a snug fit, and when keyed shall be entirely free from lost motion. 
The distance from the end of the shaft or trunnion to the inside face of the 
head shall be 15| inches in the head for the driving end of the rattler and 
llf inches long for the other head, and the distance from the face of the hubs 
to the inside face of the heads shall be 5i inches. 
The heads shall be not less than f inch nor more than £ inch thick. In out- 
line each head shall be a regular 14-sided polygon inscribed in a circle 28f 
inches in diameter. Each head shall be provided with flanges not less than 
f inch thick and extending outward 2\ inches from the inside face of the head 
to afford a means of fastening the staves. The surface of the flanges of the 
head must be smooth and must give a true and uniform bearing for the staves. 
To secure the desired true and uniform bearing the surfaces of the flanges of 
the head must be either ground or machined. The flanges shall be slotted on 
the outer edge so as to provide for two f-inch bolts at each end of each stave, 
said slots to be it inch wide and 2f inches center to center. Each slot shall 
be provided with a recess for the bolt head, which shall act to prevent the turn- 
ing of the same. Between each two slots there shall be a brace f inch thick 
extending down the outward side of the head not less than 2 inches. 
There shall be for each head a cast-iron head liner 1 inch in thickness and 
conforming to the outline of the head, but inscribed in a circle 2Si inches in 
diameter. This head liner shall be fastened to the head by seven f-inch cap 
screws through the head from the outside. Whenever these head liners become 
worn down | inch below their initial surface level at any point of their surface 
they must be replaced with new ones. The metal of these head liners shall be 
