WATTLE BARK. 513 
The following figures, taken from the American Cyclopecia, showing 
the percentage of tannin contained in most of the substances mentioned 
above, cover only the variations found in excellent samples of the same 
material. The characteristics of each are also given: 
! 
Trade name. Pe re | Characteristics. 
| 
Terrajaponica - 42 to 50 | Color bad; makes little weight; leather scft and open. 
int) ae | 24 to 33 | Color light; gives some firmness; makes leather soft and pliable. 
Myrabolams ... 28 to 44 | Color yellow; makes little weight; leather mellow. 
Oak bark ...-.. 11 to 13 | Nearly colorless; gives good weight; makes leather very firm and solid. 
Hemlock bark . 11 to 13 | Color red; gives good weight; makes leather firm and hard. 
Valonia........ 34 to 40 | Color fair; gives weight; makes leather hard. 
Divi-divi- -.-.-.-| 26 to 50 | Color poor; gives great weight. 
Mimosa bark ..| 24 to 36 | Color very red; gives weight; makes leather hard and brittle. 
It will be seen that analyses made of these substanees by distin- 
guished chemists vary widely in their results. For this reason, the 
tables given cannot be depended upon. Intelligent tanners are not, 
however, guided in their selection of tanning materials by the absolute 
percentage of tannin alone, but follow rules based on their own expe- 
rience. The color, general appearance, solidity, pliability, and many 
other conditions which constitute good leather must be taken into con- 
sideration. These depend upon other things than the mere amount of 
tannin contained in the barks or other substances which are employed, 
and have, of course, a corresponding influence upon their price. 
In the United States and England oak-tanned leather is regarded by 
many as the best. In this country it always brings a higher price than 
hemlock-tanned leather, not only because it is supposed to be more 
durable, but because of its light color. The coloring matter and resin 
contained in the hemlock have a tendency to make the leather harder 
and more brittle, and also to make it of a dark reddish hue that is not 
liked so well as the bright light appearance of that tanned with oak. 
Another reason for the greater popularity of the oak-tanned leather is 
that both in the United States and England all supplies for government 
use are required to be of this tannage. 
Gambier, or terra japonica, is extracted from the leaves of the Uncaria 
gambir, a shrub cultivated in the countries lying on both sides of Malacca. 
It is obtained by boiling the leaves in water and evaporating, then 
adding a little sago to give it consistency. 
Cutch is extracted from the acacia catechu, a tree which grows to the 
height of twenty or thirty feet on the coast of Malabar. The heart and 
bark of the wood are boiled in water and the solution evaporated. 
Divi-divi is a pod of a shrub a native of South America and the West 
Indies. The tannin is concentrated in the rind of the pod. 
Myrabolams is the commercial name of the dried fruit of the Molue- 
canna imported mainly from the East Indies. 
Valonia is the name given in commerce to the acorn cups of the 
prickly capped oak, quercus aegilops which grows abundantly in the Morea 
and adjacent countries, and also in India. 
The results obtained by tanning with valonia are almost if not fully 
the same as when the best qualities of bark are employed. It makes 
hard, firm leather, harder and less permeable to water than that made 
with oak bark, and also presents the advantage of readily depositing a 
rich bloom upon the leather. a . 
33 AGR e* 
