36 
BULLETIN 1500, U. S. DEPARTMENT OF AGRICULTURE 
be either allowed to thicken on the wood, or should be mixed thicker. 
Animal glue is at the best consistency for pressing just before it has 
formed a jelly. This consistency is obtained when the glue solution 
do 
90 
100 1/0 IZO 130 140 
Tempera ture-Peyrees F. 
Figure 7. — Relation between temperature and viscosity of an animal-glue solution 
mixed for woodworking. The tests were made on an animal glue, equivalent to 
about a No. 12 in the National Association of Glue Manufacturers grades, mixed 1 
part dry glue to 2% parts of water. 
is thick enough to form short, thick strings when touched with the 
finger, but not thick enough to resist an imprint or a depression 
readily. 
