VITRIFIED BRICK PAVEMENTS FOR COUNTRY ROADS. 35 
THE OPERATION OF THE TEST. 
Item 10. The 'brick charge. — The number of brick per test shall be 10 for all 
bricks of so-called "block size," whose dimensions fall between from 8 to 9 
inches in length, 3 to 3| inches in breadth, and 3| inches to 4i inches in thick- 
ness. 1 No brick should be selected as part of a regular test that would be 
rejected by any other requirements of the specifications under which the pur- 
chase is made. 
Item 11. Speed and duration of revolution. — The rattler shall be rotated at a 
uniform rate of not less than 29i nor more than 30£ revolutions per minute, 
and 1,800 revolutions shall constitute the test. A counting machine shall be 
attached to the rattler for counting the revolutions. A margin of not to exceed 
10 revolutions will be allowed for stopping. Only one start and stop per test 
is generally acceptable. If from accidental causes the rattler is stopped and 
started more than once during a test and the loss exceeds the maximum per- 
missible under the specifications, the test shall be disqualified and another 
made. 
Item 12. The scales. — The scales must have a capacity of not less than 300 
pounds and must be sensitive to one-half of an ounce and must be teste'd by a 
standard test weight at intervals of not less than every 10 tests. 
Item 13. The results. — The loss shall be calculated in percentage of the 
initial weight of the brick composing the charge. In weighing the rattled brick 
any piece weighing less than 1 pound shall be rejected. 
Item 14. The records. — A complete and continuous record shall be kept of 
the operation of all rattlers working under these specifications. This record 
shall contain the following data concerning each test made : 
1. The name of the person, firm, or corporation furnishing each sample tested. 
2. The name of the maker of the brick represented in each sample tested. 
3. The name of the street or contract which the sample represented. 
4. The brands or marks upon the bricks by which they were identified. 
5. The number of bricks furnished. 
6. The date on which they were received for test. 
7. The date on which they were tested. 
8. The drying treatment given before testing, if any. 
9. The length, breadth, and thickness of the bricks. 
10. The collective weight of the 10 large spherical shot used in making the 
test at the time of their last standardization. 
11. The number and collective weight of the small spherical shot used in 
making the test at the time of their last standardization. 
12. The total weight of the shot charge after its last standardization. 
13. Certificate of the operator that he examined the condition of the machine 
as to staves, liners, and any other parts affecting the barrel and found them 
right at the beginning of the test. 
14. Certificate of the operator of the number of charges tested since the last 
standardization of shot charge. 
15. The time of the beginning and ending of each test and the number of 
revolutions made by the barrel during the test as shown by the indicator. 
16. Certificate of the operator as to number of stops and starts made in each 
test. 
1 Where brick of larger or smaller sizes than the dimensions given above for blocks are 
to be tested, the same number of bricks per charge should be used, but allowance for the 
difference in size should be made in setting the limits for average and maximum rattler 
loss. 
