10 BULLETIN 1194, U. S. DEPARTMENT OF AGRICULTURE. 
moisture from humid air very quickly. The dried beans were coarsely 
broken in the coffee mill in such a way as not to rupture the seed cap- 
sules, and the resulting material was shaken in a 3-millimeter sieve, 
through which only pod and sugary material passed. The material 
remaining on the sieve, consisting of the seed capsules, was further 
ground in the coffee mill, with the burrs set about 4 millimeters 
apart. This grinding rubbed off most of the sugary pulp material 
but broke few of the seed capsules, if any. After a second sieving on 
the 3-millimeter sieve the seed capsules were quite clean. The 
sugary material passing through the sieve was, of course, combined 
with the pod material. The burrs of the coffee mill were now set a 
little closer (from 2.4 to 3.2 millimeters apart), and the seed 
capsules were ground slowly through the mill. After putting 
the material through twice and sifting the smaller seeds through 
the 3-millimeter sieve, the material remaining on the sieve contained 
the broken capsules or husks and most of the whole seeds. 
The small seeds passing through the 3-millimeter sieve, for the most 
part imperfect, are identified as second-grade seeds. The seeds and 
broken husks remaining on the 3-millimeter sieve were separated 
in the model grain and bean cleaner, and behaved much like threshed 
grain. The cleaner was so adjusted that the material passing through 
a screen having 4.8-millimeter circular holes was subjected to the 
action of the blower fan which completed the separation of seed 
from husks. Thus by the process described an excellent separation 
of the original dried beans into pod material, husk material, and seeds 
was secured. 
Next the first-grade seeds were milled by means of the mortar and 
pestle. They were first " tempered" by having about 5 per cent of 
their weight of water added and being allowed to stand overnight in a 
closed vessel in cold storage. This softened and made somewhat 
elastic the seed coats, without affecting the kernel material. The low 
temperature inhibited fermentation. The tempered seeds were 
broken in the coffee mill, care being taken not to break the seed coats 
any more than could be helped. The broken seeds were rubbed in 
the mortar, using sufficient pressure on the pestle to grind the kernel 
material to a meal. The more elastic integuments were not broken 
to any great extent. The action of the coffee mill and mortar and 
pestle on the tempered seeds resembles that of the several breaks in a 
flour mill on tempered wheat. The well rubbed material was sifted 
through a 20-mesh sieve, and the seed coats remaining on it were 
returned to the mortar for further rubbing. Eventually a large part 
of the seed coats was rubbed free or practically free from kernel ma- 
terial. The material passing through the 20-mesh sieve, which 
contained all of the kernels and a small quantity of disintegrated seed 
coats, was further rubbed and sifted through a 40-mesh sieve. This 
" reduction" process, similar to that employed in a flour mill, was 
continued until only two main products and a small quantity of 
material containing a little of the seed coats, designated " shorts," 
were finally obtained. So little of this " shorts " material was obtained 
that it was combined with the kernel material. 
The relative quantities of the several portions of the mesquite bean 
obtained by this mechanical separation and their chemical composition 
are shown in Table 6 
