Vol. XVII. No. 423 



THE AGRICULTURAL NEWis 



red cedar {Cedrcla odorata.) The example might well 

 be followed in many places in some of these .smaller 

 islands, with the same tree or some other valuable 

 wood, .as tor instance, in Antigua and the Virgin Islnnds 

 In an island like Barbados, which depends for firewood 

 almost entirely on importations from other places, 

 it would seem to offer a paying investment to replace 

 oti the not inconsiderable areas behind the beaches the 

 present haphazard growth of manchineel, whitewood, 

 and almond with regularly grown woods of L'asuarina 

 for instance, which would yield in from ten to fifteen 

 years a valuable crop of firewood, continuing to do the 

 same at intervals of two to three years for a long 

 subsequent period. 



THE CHROME-TANNING INDUSTRY. 



In view of the interest which is at present dis- 

 played in the development of local tanneries in the 

 West Indian islands, which has been noticed in recent 

 issues of this Journal, the following extracts from an 

 article in The Board of Tmd< Jourvcd. May ft, 1918, 

 may be of interest: — 



Tanning by means of ehiomiuiu compounds has been 

 very much more extensively developed in Germany and the 

 United folates of America than in the United Kingdom. 

 German and American manufacturers quickly realized the 

 value of the new method and made such rapid progress in 

 the practice of the various processes that they were able to 

 sell in the L'nited Kingdom at prices lower than the British 

 cost of production, and by this mean,=, to discourage tlie 

 establishment of the industry here 



There was at that time no prejudice against using 

 foreign goods at the expense of British manufacturers, and, 

 since foreign chrome-tanned 'eather possessed certain 

 obvious advantages, firitish boot manufacturers were ready 

 to purchase it. It was unfortunate that the chrome process 

 was not developed in the United Kingdom, because there 

 is no doubt that it had become a serious factor in the 

 deflection which occurred in the tannage of certain hides and 

 skins from this country to our competitors in Germany and 

 the United States of America. This movement of trade was 

 most pronounced in respect of the hides and skins exported 

 from India. 



Before the war, India exported about 'MofiOO cwt. of 

 raw hides per annum, of which the Central Empires took 

 one-half, the United States of America one-third, and the 

 remainder was divided between the United Kingdom, the 

 Netherlands, and Ita'.y. The position regarding raw goat 

 and sheep skins was just as unsatisfactory to this country. 

 The United States of America imported direct about .75 

 per cent, of the total export of r;..w goat skins of India, the 

 United Kingdom 10 per cent.. France 7 per cent., the 

 Netherlands and Belgium 5 per ^ cent., and Germany an 

 insignificant quantity. 



The position was not teit acutely here until the out- 

 break of war convulsed the world's markets, and .raide 

 its effect felt in the raw hide trades. The sudden demand 

 for footwear for the armies of this country and her Allies 



made it rssential tii;<t the noruul tanning cpaoity --.f this- 

 oountry should be materially extended. At the same time 

 fresh sources of raw materials had to be utilized, and once 

 more attention wa-^ directed to the vast piitentialities of the 

 Indian F'mpire. 



L^p to the present the tanners of the L^nited Kingdom 

 have shown a distinct, even an overwhelming, preference for 

 vegetable tannage, as distinguished froiu mineral, including^^ 

 chrome tannage The fundamental principle in both vege- 

 table and mineral tanning is the same. It may be thus 

 expres.sed in the words of a distinguished tanning authority: 

 'It is not only necessny to dry the fibres in a separate and 

 non adhesive condition, but .so as to coat them or alter their 

 chemical character that they are no longer capable of being 

 swelled or rendered sticky by water ' 



The action of chromium s-alts, whether normal or basic, 

 iin hides was first studied by Knapp {7^/c Nat in- ii/nt JVesen 

 iL'r Gt:rUi-ei, 1868). Knapp described a method of chrome 

 tanning which is identical with one of the modern proces-^es, 

 for he proposed the formation of a liasic chromium salt by 

 the addition of some compound, such as normal sodium car- 

 bonate to the chrome solution after the manner of tlie so- 

 called 'single bath' process. 



In 1684: a successful two-bath process was patented in the 

 L'nited States of America by August Schultz, and the process 

 proved a commercial success in the production of light 

 leathers. According to the Schultz process, the .skins are 

 impregnated with a sulution of potassium bichromate, acidi- 

 fied with hydrochloric acid, and the chromic acid absorbed 

 by the skins is subsequently reduced by means of sulphurous 

 acid, through the inuuersion of the skins in an aciditlod 

 solution of .sodium tliiosulphate. 



One of the main advantages of chrome tanning is the 

 rapiditj' of the process as compared with vegetable tannage, 

 and the consequent increase in the possible turn over. The 

 waterproofness and compactness of the leather after fat 

 liquoring, etc., cause it to be sought after for box-calf, glace 

 kid, and other upper leathers. The attinity for chrome tan- 

 nage varies from leather to leather. Sheep skins, horse hides 

 and kips show a smaller affinity for it than goat skins, ox- 

 hides, and especially calf skins. The further property of 

 the chromium salts of forming lakes with many mordant 

 colouring matters makes their use for tanning skins of 

 considerable interest where the production of coloured leath- 

 ers is the o'oject in view. The chrome tannage of skifis 

 entails closer technical supervision of processes than veget- 

 able tannage; but the problems it offers the chemist and 

 tanner, and the possibilities it affords of achieving all those 

 resu'ts in leather production that have given the German and 

 American tanners their advantages in the past, must necess- 

 arily appeal to [irogrcssive tanners and leather chetuists of 

 the Ignited Kingdom. 



DEPARTMENT NEWS. 

 The Impt-rial t'omuiissioner of Agriculture for the 

 West Indies, Sir Francis Watts, K ( ',M.G., has retiiruod 

 tb Barbados from his visit to .lauiaira .uid the Bahaiii;is. 



iVlr. H. A. iiiUliiii, U N., M.-Sc, has afsu rctuni.^d 

 to Barbados, on the eoiapletion of his work in Kgypb. 



