82 



LEATHER 



MIMOSA. The bark and pods of several kinds of Prosopis, the astringent properties 

 of which have rendered them valuable in tanning, are known in commerce by this 

 name. The Mimosts are a division of the leguminous order of plants, which consists 

 of a large number of species, the Acacia being the principal. The sensitive plants 

 belong to this division. The Prosopis is found in India and South America ; the genus 

 consists both of shrubs and trees. 



VALONIA. The oak which produces this acorn is the Qtiercus Mgilops, or great 

 prickly-cupped oak (figs. 1356, 1357). These are exported from the Morea and 

 Levant; the husk contains an abundance of tannin. 



1356 



1357 



1358 



CATECHU, or Terra Japonica, is the inspissated extract of the Acacia catechu. At 

 the time the sap is most perfectly formed the bark of the plant is taken off, the tree is 

 then felled, and the outer part removed ; the heart of the tree, which is brown, is cut 

 into pieces and boiled in water ; when sufficiently boiled it is placed in the sun, and, 

 subject to various manipulations, gradually dried. It is cut into square pieces, and 

 much resembles a mass of earth in appearance ; indeed, it was once considered to be 

 such, hence the name Terra Japonica. 



We give Sir H. Davy's analysis ; the first n.umbers represent Bombay, the second 

 Bengal catechu : 



Tannin 109 . .97 



Extractive 68 . .73 



Mucilage 13 . .16 



Impurities 10 . .14 



This astringent is also obtained from the Uncaria Gambir. 



DIVIDIVI is a leguminous plant of the genus Casalpinia (C. coriaria). The legumes 



of this species are extremely astringent, and contain a very large quantity of tannic 



and gallic acid ; they grow in a 

 very peculiar manner, and be- 

 come curiously curled as they 

 arrive to perfection (fig. 1358). 

 The plant is a native of America, 

 between the tropics. 



SUMACH is a plant belonging 

 to the genus Ehus; several of 

 the species have astringent pro- 

 perties ; Eh us cotinus and E. 

 coriaria are much used in tan- 

 ning ; the bark of the latter is 

 said to be the only ingredient 

 used in Turkey for the purpose 

 of converting gelatin into leather. 



That used in this country is ground to a fine powder, and is extensively applied to the 



production of bright leather, both by tanners and curriers. 



Many other vegetable products have been from time to time proposed, and to some 



extent adopted for the same end, but they need not be enumerated. 



The process first attended to by the tanner is simply to soak the skin or hide in 

 water ; those from the home market may be said to be washed merely, as they remain 

 in water only a few hours ; while hides imported from foreign countries, and which 

 have been preserved by salting or drying, and especially the latter, require soaking for 

 a longer period, in order to render them supple, and beating or rubbing materially 

 assists in bringing them to the required condition. 



