temperature of the glue solution shall be 60° C. and the determination 
made as soon as the solution has uniformly reached the required temperature. 
Jelly Strength 
The samples from the viscosity test shall "be placed in the 
standard containers and used for jelly strength determinations. The glue 
solution should he free of air or foam. The samples shall he allowed to 
cool to approximately U5° C. and any water of condensation shall he mixed 
thoroughly with the solution. The samples shall then "be placed in a 
chamber or hath at 10 i 0.1° C. for a period of l6 to 18 hours. 
The determination of jelly strength shall he made on a Bloom 
gelometer adjusted to give h mm. depression and to deliver a load of UO 
grams per second to the surface of the jelly. The test must he completed 
within 2 minutes from the removal of the sample from the cooling chamber. 
Apparent Moisture Content 
The loss in weight of a 10-gram sample, previously reduced to 
a size that will pass a No. k mesh screen, placed in a well-ventilated 
oven and heated at 105° - 3° C. for l6 hours, shall be not less than 9 nor 
more than 15 percent of the original weight of the glue. 
Neutrality 
Portions of the solutions upon which the viscosity and jelly 
strength tests were made or other samples of equal concentration shall 
be used to determine the acidity or alkalinity of the glue. The acidity 
or alkalinity shall be determined in terms of pH and must be within the 
range of 5*5 to 7»5» 
Foam 
Portions of the samples used in the viscosity and jelly strength 
tests or other samples of equal concentration shall be used for a deter- 
mination of the tendency to foam. Seventy-five cc. of the solution at 
60° C» shall be placed in the standard container and agitated with a 
stirrer or propeller. The stirrer shall be placed in the lower one-half 
of the solution and the speed of the stirrer during test shall be between 
13,000 and 15,000 r.p.m. The solution shall be agitated for 1 minute and 
then allowed to stand at room temperature for 10 minutes, at the end of 
which there shall be not more than 2.5 cm. foam. 
RU92 -L- 
