2 BULLETIN 1168, IT. S. DEPARTMENT OF AGRICULTURE. 
istry of the United States Department of Agriculture. This investi- 
gation included studies of shoe soles made from the following ma- 
terials: (1) Sole leather of typical tannages (oak bark, chestnut 
wood, and hemlock bark) ; (2) sole leather unloaded and loaded 
with glucose and epsom salts; (3) rolled and unrolled sole leather ; 
(4) low and high oiled sole leather; (5) sole and belting leather; (6) 
vegetable-tanned sole leather, chrome-tanned sole leather, and fiber 
soles; (7) waxed and unw axed chrome-tanned sole leather; (8) sole 
leather subjected to other treatments of minor importance. Several 
types of upper leather and of Army shoes were also included. 
PLAN OF INVESTIGATION. 
SELECTION OF MATERIAL. 
Bides. — In order to secure a reasonable control of the variations 
caused by differences in hides, nearly all of the vegetable-tanned sole 
leathers were made from green salted hides. A few lots, taken for 
comparison, were made from dry hides. Eighteen of the 34 lots of 
vegetable-tanned sole leather were made from " Texas" hides, which 
were used whenever possible. 
Leathers. — All leathers w^ere selected and marked by an experienced 
trade man representing the War Department and by representatives 
of the Bureau of Chemistry, who also obtained detailed information 
on the history of the leathers. Thirty-four lots of vegetable-tanned 
sole leather were secured from 19 tanners, 3 lots of vegetable-tanned 
belting leather from 3 belting concerns, 2 lots of unwaxed chrome- 
tanned sole leather from 2 tanneries, and 6 lots of waxed chrome- 
tanned sole leather from 4 tanners. With the exception of 2 broken 
lots, each lot of sole leather consisted of 10 bends. At the time these 
experiments were planned the question of the best upper leather for 
continuous, heavy outdoor service was a very live one. Hence, for 
general observations on upper leathers, the chief types of cowhide 
upper leathers were included. These consisted of (1) one lot of bark- 
tanned leather, flesh finish; (2) two lots of stuffed chrome-tanned 
leather, grain finish; (3) one lot of fat-liquored chrome-tanned leather, 
grain finish; and (4) four lots of retanned chrome leather, two flesh 
finish and two grain finish. 
Fiber soles. — From the most prominent brands of fiber soles, 96 
pairs, representing four makes, were chosen. 
PREPARATION OF MATERIAL. 
To eliminate as far as possible the difference in wearing quality due 
to the section of the hide, 3 the soles were taken from only two definite 
sections of each bend, one pair at the shoulder end, at a point directly 
above the " break" in the hide back of the forelegs, and the other 
pair at the butt end, directly above the " break" in front of the hind 
legs. These two sections, representing the extremes of the bend, were 
fixed on this physiological basis rather than by a stated measure- 
ment from a given point in the bend. 
Each lot of leather was given a serial number, the bends of each lot 
were numbered from 1 to 10, and each sole was designated by the 
number 1, 3, 4, or 6 (Fig. 1). Thus a sole numbered 2-4-1 came from 
3 J. Amer. Leather Chem. Assoc. (1918), IS: 86. 
