Y4:8 NEW YORK STATE MUSEUM 



be used, having 12 to 16 staves, with openings from one eighth 

 to three eighths of an inch between the staves, but if this is done 

 a record of it must be attached to the official report of the test. 



3 Conipoisition of the charge. All tests must be made on 

 charges composed of one kind of material at a time. ISTo test shall 

 be considered official where two or more different bricks or mate- 

 rials have been used to compose a charge. 



4 Quantity of the charge. The quantity of th© charge shall be 

 estimated by its bulk and not by its weight. The bulk of the 

 standard charge shall be equal to 15^ of the cubic contents of the 

 rattling chamber, and th© number of whole brick whose united 

 volume comes nearest to this amount shall constitute a charge. 



5 Revolutions of the charge. The number of revolutions of a 

 standard test shall be 1800, and the speed of rotation shall be 

 30 a minute. The belt power shall be sufficient to rotate the 

 rattler at the same speed whether charged or empty. Other speeds 

 of rotation between 24 and 36 revolutions a minute may be used, 

 but in this case a record of the speed must be attached to the official 

 report. 



6 Conditions of the charge. The bricks composing a charge 

 shall be dry and clean, and, as nearly as may be possible, in the 

 condition in which they are drawn from the kiln. 



Y Calculation of the results. The loss shall be calculated in 



percentage of the weight of the dry brick composing the charge, 



and no result shall be considered as official unless it is the average 



of two distinct and complete tests, made on separate charges of 



brick. 



Specifications for absorption test 



1 The number of bricks for a standard test shall be five. 



2 Th© test must be conducted on rattled bricks. If non© such 

 are available, the whole bricks must be broken in halves before 

 treatment. 



3 The bricks should be dried for 48 hours at a temperature 

 ranging from 230° to 250° F. before weighing for the initial dry 

 weight. 



