96 
MANUFACTURE OF RUBBER FROM THE GUAYULE 
PLANT 
The guayule plant, Parthenium argeniatum, occurs in the 
central plateau of Mexico, and in its extension, the Stockton 
Plateau of Texas. There has recently been established at Mara- 
thon, Texas, a factory for the manufacture of rubber from the 
plants which grow in that vicinity, embracing the whole of the 
area of distribution in Texas. Through the courtesy of Mr. 
W. H. Stayton, I have been able to transmit to the museum of 
the New York Botanical Garden a suite of specimens illustrating 
the various stages in the process of manufacture. The more 
important steps in this process are as follows : 
The shrub is collected in the field by pulling it up by hand. 
It is then brought to a central point, called a guayule camp, where 
it is packed into bales in the fashion of baled hay. From this 
point, it is hauled to the factory, a distance of 50 to 100 miles 
according to the location of the camp. Arrived at the factory, 
the weight of each bale is recorded for the purpose of comparison 
with the field weight at the time of baling and for the purpose 
also of establishing data so as to show the percentage of returns. 
The bales are stacked in the factory yard until seasoned, since 
the extraction does not go on well if the fresh shrub is use 
The first step in the actual factory process is a crushing of the 
shrub between corrugated rollers moving at differential speed. 
The comminuted shrub, a sample of which is shown in 
is then placed in a pebble mill. This is a short drum, containing 
a charge of Norwegian or Mediterranean flint pebbles, a certain 
amount of water and the amount of shrub to be ground. The 
mill is rotated on its axis at a certain rate of speed for certain 
length of time, at the end of which the shrub is found to be 
finely ground and the rubber more or less separated from the 
the bagasse, that is, the fiber, et cetera, of the shrub, and occurs 
in the form of small rounded particles, more or less adherent 
to each other, called ‘‘worm-rubber.” The mill is now dis- 
charged, the water, rubber and bagasse being led through ditches 
toa skimming tank. This material, as it passes from the pebble 
mill to the skimming tank, is illustrated in jar no. 3. It will be 
