January, 1909.] 



1? 



Dyes and Tans, 



In endeavouring to invite public at- 

 tention to the immense possibilities that 

 lie in the direction of the systematic 

 exploitation of some of the commoner 

 Indian acacias as sources of tannin, it 

 must be mentioned that the moderate- 

 sized, diffuse-branching, gregarious 

 species, botanically known as the Acacia 

 arabica, is certainly one of the most 

 neglected but valuable. Although the 

 quality of the bark of this acacia is 

 inferior to that of the Australian wattle 

 and even to that of the Acacia catechu, 

 the extent of distribution of the species 

 in India and the numbers in which they 

 occur there are such as to warrant the 

 conclusion that its systematic exploit- 

 ation for tannin-extraction is likely to 

 meet with favourable results by retriev- 

 ing in quantity what it cannot in quality. 

 The natural regeneration of the tree 

 being easy but somewhat slow from seed, 

 its artificial reproduction, for economic 

 purposes, could be more successfully 

 accomplished by the creation and 

 development of shoots and suckers from 

 the stool. For this the tree requires to be 

 coppiced at suitable intervals, from 

 time to time. The safest period, con- 

 sistent with utility, of the economic 

 exploitability of the species, is said, on 

 good authority, to be ten years, — 

 the age at which the bark has been 

 found to be mature enough to contain 

 tannin of sound and serviceable quality. 

 At this age, too, the possibility is 

 greater than at any other recently 

 anterior one of obtaining an appreciable 

 quantity (half a ton) of bark from each 

 tree, that will have been coppiced. 

 With the yield of tannin at 15 per cent, 

 (actual experiment giving 18'y5) a tree 

 would produce 168 pounds of the sub- 

 stance at the close of the teuth year of 

 its age. Thereafter, the yield, which 

 improves with coppicing, would directly 

 depend on the number, size, and vigour 

 of the shoots which would be permitted 

 to develop on the stool from those given 

 out after each periodic felling. As 

 regards the other Indian acacias, in- 

 formation of a reliable nature relating 

 to the yield of tannin from the bark is 

 at present unavailable. The important 

 Khair (Acacia catechu) itself is seldom 

 looked upon as a source of tannin, 

 outside the great and well known 

 capacity of its wood as a yielder of 

 catechu or catechu-tannin (catechiu). 

 No endeavour, beyond the local and, 

 therefore, comparatively limited appli- 

 cation of its bark as a tanning material, 

 has as yet been made in Iudia To 

 obtain the catechu the tree is felled and 

 its heartwood cut up into chips and 

 boiled. The bark, however, with its 

 stores of tannin, is usually left to rot on 

 3 



the ground. Some idea of the extent to 

 which this wastage of a useful and 

 valuable raw material now takes place 

 in the country may be gained from the 

 fact that throughout the wide area of 

 its distribution thousands of trees are 

 annually felled. Why, when the wood 

 is being boiled for catechu, or otherwise 

 utilized throughout the country, the 

 bark is not at the same time treated for 

 the manufacture of an extract which 

 assuredly contains a high percentage of 

 tannin of good quality is a question 

 which so far appears to have been pro- 

 vocative of no reasonable or satisfactory 

 response. The fact, at any rate, seems 

 to savour of some of that sublimely 

 supine indifference which the son of the 

 soil has been proverbial for displaying 

 in treatment of great and glorious 

 heritage — a mine of wealth whose super- 

 ficial veins themselves still largely wait 

 upon his consideration. 



Besides the two indigenous acacias 

 described above as sources of tannin, 

 the undermentioned Indian species, too, 

 deserve our best attention in India : — 



(1) Acacia Farnesiana, Willd. — A low 

 erect shrub or small tree occurring 

 throughout the plains of India and 

 Burma ; it has bright yellow flowers 

 that are fragrant and arrauged in the 

 axils of the leaves ; it is armed with long 

 straight spines. 



(2) Acacia ferruginea, D. C. — A large 

 deciduous tree with reddish brown 

 bark ; armed with short, hooked, double 

 spines, the flowers occurring in axillary 

 peduncled spikes. 



(3) Acacia jacquemontu, Benth. — A 

 small elegant bushy shrub with smooth 

 stem and straight, slender, shining 

 spines ; flowers like those of (1). 



(4) Acacia Latronum, Willd. — A small 

 tree or shrub of Southern India, occur- 

 ring in gregarious thickets ; its flowers 

 are given out in numerous spikes from 

 the nodes of the branchlets when the 

 tree is leafless and double spines are 

 long and straight. 



(5) Acacia planifrons, W. and A. — A 

 species similar to (4) in habit and dis- 

 tribtuion but with grey lenticels in 

 place of spines, (l)and (5) form flattened 

 tops that are very conspicuous and 

 remarkably typical of the dry open 

 forests in which they occur. 



(6) Acacia leucophlcea, Willd.— A large 

 deciduous tree with short, straight, 

 white spines, flowers in small heads 

 borne on long terminal tomentose 

 panicles. 



(7) Acacia modesta, Wall. — A small 

 tree with short, hooked, double spines 

 and small sparse, greenish yellow spikes 

 of flowers. 



