4 BULLETIN 1065, U. S. DEPARTMENT OF AGRICULTURE. 
the weight of its contents may be determined directly in terms of 
pounds per bushel by means of the counterpoise and the graduations 
on the beam. As there are 32 quarts to the bushel, the beam is gradu- 
ated to indicate 32 times the actual weight of the contents of the 
kettle ; therefore, 1 pound in the kettle is equivalent to 32 pounds 
per bushel on the beam, 1 ounce to 2 pounds, \ ounce to 1 pound, etc. 
When these facts are borne in mind the necessity for great care in 
following the prescribed method in making the weight-per-bushel test 
and for having an accurate kettle and beam will be realized. 
The apparatus for determining weight-per-bushel tests shown in 
figure 1 and the method of making the test have been carefully de- 
veloped and are officially approved. It has been demonstrated that 
if the prescribed method is followed and the apparatus is accurate, 
weight-per-bushel determinations can be made rapidly and accur- 
ately by any one familiar with the test. The two main factors af- 
fecting the accuracy of "test weight" determinations are the method 
used in making the test, and the accuracy of the apparatus. Whether 
or not the proper method is used depends entirely upon the person 
making the test, as the official method is clearly defined, but the 
most careful application of the prescribed method will not give ac- 
curate results if the apparatus used in making the test is insensitive 
or incorrect. The accuracy of the apparatus depends first, upon the 
capacity of the- test kettle, and second, upon the correctness of the 
weighing mechanism. If the apparatus is purchased from a reliable 
manufacturer both the kettle capacity and the beam are usually 
accurate when it leaves the hands of the factory inspector, but even 
if it is absolutely correct at that time, it may not be correct when set 
up in the office or laboratory. No test- weight device should be used 
for determining grades of grain until it has been checked for ac- 
curacy by a properly conducted test, and this test should be repeated 
periodically as a general precaution. In addition to the periodic 
tests a special test should be made whenever the device has been 
shipped and particularly whenever any deformation of either kettle 
or beam is noticed. Any kettle or beam which has been deformed 
by bending or denting enough to render such deformation visible 
should be considered incorrect until a thorough test has been made. 
Methods of checking the capacity of the standard quart test kettle 
and the accuracy and sensitiveness of the beam have been developed 
and are given on pages 8 and 11. 
When the test weight per bushel of grain is determined with the 
standard apparatus in correct adjustment and with careful applica- 
tion of the correct method of use, uniform results are obtained. 
