July, 1909.] 



9 



DYES AND TANS. 



TANNING MATERIALS. 



(From the Report on the Work of the 

 Imperial Institute, 1906-1907, No. '584.) 











Samples 





Samples 





Samples 





awaiting 





reported on 



6 



reported on 



o 



investigation 



d 



during' 1906, 





Murine 1Q07 





«U u LI c mill OI 













1907. 





Transvaal 



1 



Gambia 



1 



ijoiu L-oast . . 



I 



Qganda 



2 



Sierra Leone 



1 



Foreign Coun- 





Somaliland .. 



3 



Gold Coast . . 



1 



tries 



3 



Sudan 



1 



Transvaal ... 



1 







Seychelles . . 



1 



Cape Colony 



10 







India 



U 



Uganda 



3 







Western Aus- 





Sudan 



2 







tralia 



3 



Seychelles . 



12 







British 





British Hon- 









Guiana 



1 



duras 



4 











Bazil 



1 







Total 



'26 



Tot:il 



36 



Total 



4 



1906. — None of the samples of tanning 

 materials examined proved to be suffi- 

 ciently rich in tanning to be worth con- 

 sideration for export to the United 

 Kingdom, but most of them were ol 

 fair quality and suitable for local use 

 in tanning. This is the case, for ex- 

 ample, with the three interesting mate- 

 rials from Somaliland, viz., "Wattu" 

 leaves derived from Osyris abyssinica, a 

 near relative of the plant which yields 

 the so-called "Cape Sumach," " gallol 

 root bark," from a species of Acacia 

 near Acacia latronum, and " rnaua 

 bark," of unknown botanical origin. 

 These yielded respectively 24*8, 24*0 and 

 13-7 per cent, of tannin. The two first- 

 mentioned furnished leathers of medium 

 quality, whilst that prepared with rnaua 

 bark was of fair quality, but rather 

 harsh and somewhat dark coloured. 



The samples from India were extracts 

 prepared from the barks of Shorea 

 robusta, Terminalia tomentom and 

 Rhizophora mucronata. Of these the 

 most promising were those prepared 

 from the lastnamed bark. They con- 

 tained high percentages of tanning, but 

 were rather dark coloured, indicating 

 the need for greater care in evaporating 

 the liquors prepared as a first step in the 

 manufacture of the extracts. 



1907. — The samples from Cape Colony 

 included six samples of wattle bark 

 derived from the golden wattle, A cacia 

 pycnantha, and the black wattle, Acacia 

 decurrens. All these proved to be of 

 good quality and similar in type to the 



2 



wattle barks now imported from Natal 

 and Australia. They were valued from 

 £1 10s. 0d. to £1 15s. Od. per ton. 



The other samples from Cape Colony 

 were samples of barks from indigenous 

 trees, " White thorn " (Acacia horrida), 

 " Krupeehout," "Kliphout," and of Cape 

 Sumach. These were all of poorer 

 quality than the wattle barks, and most 

 of them though suitable for local use 

 were of no value for export. 



The samples from Uganda included 

 " Busana bark," derived from a species 

 of Acacia, probably Acacia spirocarpa. 

 This is being used in the neighbourhood 

 of Entebbe as a tanning material. It 

 contains about 10 percent, of tannin and 

 yields a rather harsh, dark-coloured 

 leather, and should only be used in 

 admixture with the better materials 

 imported to Uganda from India. A 

 sample of the bark of Terminalia 

 velutina was also received from Uganda. 

 This contained 12 per cent, of tannin and 

 yielded a light-coloured leather of fair 

 quality. 



The Sudan materials were samples of 

 Kili bark from ficus sp. and " Alimu " 

 bark from Xvnenia americana. The 

 latter proved to be of fair quality for 

 local use. 



The samples from Gambia, Sierra 

 Leone, Gold Coast Colony, Seychelles 

 and British Honduras were all mangrove 

 barks. Of these samples certain of those 

 from Seychelles alone yield sufficient 

 tannin (i.e., over 40 per ceut.) to be 

 worth consideration for export. The 

 other samples could only be used locally 

 for tanning or for the manufacture of 

 tanning extracts. The samples from 

 British Honduras and the Gambia, 

 however, included barks which were 

 of special interest on account of 

 the unusually good and light-coloured 

 leather they produced for mangrove 

 barks. The examination of this large 

 collection of mangrove barks has enabled 

 some useful information to be obtained 

 regarding the value of scraping off the 

 outer bark before shipment, and it seems 

 certain that in most cases the outer bark 

 contains little or no tannin, and its 

 removal before export raises the average 

 tannin content of the bark and reduces 

 the bulk. 



The sample from Brazil was " barba- 

 timao bark" sent by the British Consul 

 at Rio de Janeiro with a view to 

 ascertaining whether this material, 

 largely used in Brazil for tanning, is of 

 commercial value. The sample proved 



