4 BULLETIN 899, U. S. DEPARTMENT OF AGRICULTURE. 
In some cases where the free acid contents of the rosin oil are low, 
the mixture will saponify very slowly, and when fully saponified the 
finished product will be so soft that it will not stand up on the trees, 
even at moderate temperatures. In order to remedy this, it is neces- 
sary to add more rosin oil to bring the acid content up to the required 
amount, so that the product will set properly and remain intact on the 
trees during high summer temperatures. On the other hand if this 
method is used, and it requires very much rosin oil to bring about the 
proper saponification, the resultant product, which will have a larger 
percentage of rosin oil, is made tougher, and when placed on the trees 
will film over much more quickly. 
Rosin oils low in viscosity but highly acid, though they set very 
quickly, will give a product which will not as a rule have body 
enough to stand up well at high temperatures, while rosin oils with a 
viscosity of 52 or higher contain about the right amount of acid to 
saponify the mixture thoroughly and make the resultant product of 
the right consistency to stand up and remain efficient at high tempera- 
tures. 
D. Ordinary commercial hydrated lime. 
This product, known as hydrated lime, is sold commercially and 
can be bought in 50-pound bags. If this can not be obtained ordinary 
rock or quick lime can be used, and this should be slaked with just 
enough water to make the resultant product a dry powder or hydrated 
lime. This should be passed through a sieve having 14 meshes to the 
inch. A coarser mesh should not be used. 
EQUIPMENT USED. 
The banding material was mixed in a 25-gallon soap kettle (fig. 1), 
which was equipped with a stirring arrangement, having double pad- 
dles turning in opposite directions. The mechanism used to turn the 
paddles in opposite directions was part of the rear end assembly 
of a light automobile. The axle shaft turned in one direction and a 
small length of iron pipe inclosing this shaft to about half way down 
from the top was so attached that it would turn in the opposite direc- 
tion. To this axle and iron pipe, respectively, were attached double 
paddles so shaped that the material was kept moving in all direc- 
tions, thereby making an even mixture. Two pairs of paddles, A 
and B, which were attached to the outer shaft, moved in one direction, 
and C and D, attached to the inner shaft, moved in the opposite direc- 
tion. This was operated by a belt from the shafting of the machine 
room in the basement of the storehouse mentioned above. The speed 
of the machine was timed to allow the paddles to turn 30 revolutions 
per minute. The kettle used was provided with a steam jacket, but 
usually no heat was required. At low temperatures both the rosin 
oil and coal-tar neutral oil become rather thick, and do not mix well, 
