June 1, 1912.] 



THE INDIA RUBBER WORLD 



425 



sulphate being about 4.3, and that of zinc sulphide 3.8, it is 

 conceivable that by varying the proportion of these two constitu- 

 ents, the resulting gravity of the lithopone could vary. In 

 reality, this is not the case, because lithopone, although a mix- 

 ture should have a perfectly definite and constant composition, 

 consisting roughly of 70 per cent, barium sulphate and 30 per 

 cent, zinc sulphide. Simply mixing these two chemicals in the 

 proportions stated would not result in the brilliantly white 

 product which w-e know as lithopone. This is prepared by add- 

 ing a solution of barium sulphide to a solution of zinc sulphate. 

 There is thereby produced zinc sulphide and barium sulphate, 

 both of which are insoluble and precipitate out. If now any 

 remaining barium sulphide or any remaining zinc sulphate (ac- 

 cording to which was used in excess), is dissolved out by 

 means of water, the remaining lithopone will always have the 

 same composition. Accordingly its actual gravity is also con- 

 stant. 



I should not like to be interpreted from anything that has 

 been said above, as being opposed to the employment of com- 

 pounding ingredients in a fine state of subdivision. But I do 

 wish to point out that a manufacturer who buys a mineral filler 

 of apparently lower gravity, under the impression that its em- 

 ployment will make his compound of proportionately lower 

 gravity, is deceiving himself. 



THE FUTURE OF GERMAN COLONIAL RUBBER 

 GROWING. 



DASED on hjs recent visit to the German colonies in East 

 ■'-' Africa, noticed in the March issue of The India Rubber 

 World (page 269), Dr. Eduard Marckwald, of Berlin, lately read 

 an interesting paper before the German Agricultural Society, of 

 which a reprint has come to hand. Having in his previous utter- 

 ances dealt with the present conditions and prospects of rubber 

 plantations in German East Africa, he has in the above-named 

 paper taken up the broader question of the ultimate vitality of 

 German rubber plantations in general. 



Official statistics, quoted in the April issue of the India Rubber 

 World (page 324) showed the following results: 



RUBBER EXPORTS FOR YEARS ENDING APRIL. 1910 AND 1911. 



1910. 1911. 



Kamerun tons 1,518 1.962 



German East Africa 474 744 



Togo 137 135 



German New Guinea 6 8 



2.849 



Total from German possessions. . ./o;ii 2,135 



KAMERUN AND TOGO. 



These figures showing for 1911 a total of nearly 2,100 tons ex- 

 rorted by Kamerun and Togo, as compared with about one-third 

 that quantity from German East Africa, illustrate and confirm 

 Dr. Marckwald's discrimination between conditions in the first 

 named possessions and those in East Africa. To use his own 

 words : "Labor conditions in Kamerun are relatively satisfactory, 

 the wages being suitable, and the natives capable of undertaking 

 complicated work. The cost of producing Kick.via (including 

 freight to Hamburg and selling expenses there) amounts to less 

 than 3 marks per kilo (33 cents per pound)." 



Such a price, he adds, renders Kamerun practically able to com- 

 pete in the world's markets, even if quotations materially recede. 

 His own question he answers in the following terms: "The pro- 

 spective vitality of Kamerun plantations can therefore be confi- 

 dently asserted, with the proviso that the trees continue to yield 

 and that they withstand repeated tappings." 



With regard to Togo, Dr. Marckwald remarks that owing to 

 the satisfactory labor conditions there prevailing, there is no rea- 

 son to anticipate the non-success of plantations in that colony, as 

 they are being developed in a favorable and systematic manner. 



KICKXIA AND HEVEA IX KAMERUN. 



The preponderance of Kickxia in Kamerun is indicated by the 

 following oflicial estimate of the trees in that colony at the end 

 of April, 1911: 



Kickxia '. trees 4,915.865 



Hevca 786,270 



Manihot 19.343 



Ficus 16,686 



CastiUoa 2,584 



Sundry varieties 3.500 



Total 5,744,248 



In connection with this estimate interest attaches to Dr. Marck- 

 wald's anticipation (based upon the climatic conditions existing), 

 that although important yields from the later plantings of Hcvea 

 are not yet available, that tree, owing to its hardier and more 

 reliable qualities, will gradually supplant Kickxia, notwithstand- 

 ing the lower cost of production in the latter case. 



GERMAN EAST AFRICA. 



Conditions in German East .Africa are, however, radically dif- 

 ferent from those existing in the other German colonies; all of 

 which, with the exception of Southwest Africa, are more or less 

 interested in rubber. According to Dr. Marckwald's observa^ 

 tion, cultivation (not only of rubber) is carried on to an appre- 

 ciable extent in East Africa by laborers, who are devoid of ex- 

 perience in plantation work, and even ignorant of or- 

 dinary .Tgricultural operations. Hence there is no due preparation 

 of the soil and no investigation as to whether the land to be 

 planted is suitable for the purpose to which it is to be applied. 



Among the points to which attention is called in the paper, are 

 the more thorough preparation, fertilization and (where neces- 

 sary) artificial irrigation of the soil, in addition to care in the 

 choice of seeds. Planting trees too closely and at the wrong 

 time is condemned by Dr. Marckwald, following up his previous 

 remarks on those subjects; while the present system of tapping 

 is likewise criticized, as well as the mode of packing. 



TO VV.\SH ALL EAST AFRICAN RUBBER IN EUROPE? 



After dealing with the unfavorable ccrditions now attending 

 the washing of rubber in German East Africa, which, it is re- 

 marked, are largely due to the present system of tapping. Dr. 

 Marckwald suggests, until the question of tapping is settled in a 

 satisfactory manner, the establishment in Germany of a rubber- 

 washing plant, through which all East-African plantation rubber 

 would have to pass before reaching the market. Such an estab- 

 lishment would be under official and permanent expert superin- 

 tendence, and of a size capable of washing one ton per day, and 

 would not cost more than the equivalent of six to seven thousand 

 dollars. In this connection reference is made to the new machine 

 of Werner & Pfleiderer, in which there is scarcely any friction, 

 with the result that the rubber is subjected to milder treaiment 

 than is now usual in the process of washing. 



While referring to the partial progress in the direction of the 

 needed reforms, made during his recent visit to German East 

 Africa, Dr. Marckwald expresses the hope that the question of 

 producing rubber, satisfactory both in quality and quantity, will 

 be solved through serious work ; thus facilitating the establish- 

 ment of a standard quality of rubber, which matter has become a 

 vital question for the German colonial possessions. Without 

 cheaper and better products, he adds, the rubber plantations of 

 German East Africa are doomed to hopeless failures. 



A BOOK for rubber planters — Mr. Pearson's "What I Saw in 

 the Tropics." 



The accepted authority on South .American rubber — "The 

 Rubber Country of the Amazon." by Henry C. Pearson. 



