34 BULLETIN 373, U. S. DEPARTMENT OE AGRICULTURE. 
and shall be securely bedded in broken stone, gravel, or firm earth. In pre- 
paring the trenches for the curbs great care shall be exercised to see that the 
material upon which the curb is to be set is well compacted, firm, and hard. 
Stone curbing shall be quarried from hard, tough, homogeneous stone. The 
individual blocks shall have the cross section shown on the plans and shall 
be not less than four (4) feet in length. Each block shall be free from seams 
and all other imperfections and shall be neatly dressed and finished on all 
exposed faces. 
APPENDIX B. 
Method for Inspecting and Testing Paving Brick. 1 
The quality and acceptability of paving brick, in the absence of other special 
tests mutually agreed upon in advance by the seller on the one side and the 
buyer on the other side, shall be determined by the following procedure, viz : 
(1) The rattler test, for the purpose of determining whether the material as 
a whole possesses to a sufficient degree, strength, toughness, and hardness ; 
(2) Visual inspection, for the purpose of determining whether the physical 
properties of the material as to dimensions, accuracy and uniformity of shape 
and color are in general satisfactory, and for the purpose of culling out from 
the shipment individually imperfect or unsatisfactory brick. 
The acceptance of paving brick as satisfactorily meeting one of these tests 
shall not be construed as in any way waiving the other. 
SECTION 1.— THE RATTLER TEST. 
THE SELECTION OF SAMPLES FOE TEST. 
Item 1. Place of sampling. — In general where a shipment of brick involving a 
quantity of less than 100,000 is under consideration, the sampling may be done 
either at the brick factory prior to shipment, or on cars at their destination, or 
on the street when delivered ready for use. When the quantity under consider- 
ation exceeds 100,000, the sampling shall be done at the factory prior to ship- 
ment. Brick accepted as the result of tests prior to shipment shall not be 
liable to subsequent rejection as a whole, but are subject to such culling as is 
provided for under Section II (Visual Inspection). 
Item 2. Method of selecting samples. — In general the buyer shall select his 
own samples from the material which the seller promises to furnish. The 
seller shall have the right to be present during the selection of a sample. 
The sampler shall endeavor, to the best of his judgment, to select brick repre- 
senting the average of the lot. No samples shall include brick which would 
be rejected by visual inspection as provided in Section II, except that where 
controversy arises, whole tests may be selected to determine the admissibility 
of certain types or portions of the lot having a characteristic appearance in 
common. In cases where prolonged controversy occurs between buyer and 
seller, and samples selected by each party fail to show reasonable concurrence, 
then both parties shall unite in the selection of a disinterested person to select 
the samples, and both parties shall be bound by the results of samples thus 
selected. 
Item 3. X umber of samples per lot. — In general one sample of 10 brick 
shall be tested for every 10.000 brick contained in the lot under consideration, 
1 Recommended by subcommittee on paving brick of the American Society for Testing 
Materials. 
