and Magazine of the Ceylon Agricultural Society.— December, 1911. 



581 



have been sure of ifc. "Isoprene" identified it. 

 After this for some years chemists experimented 

 with ways of turning back tho isoprene into 

 rubber. Tilden once found a bottle of isoprene in 

 his laboratory that had somehow converted itself 

 partially into rubber, or caoutchouc ; and he 

 believeu he had found a less accidental method 

 by treating it with hydrochloric acid. But other 

 cUemi6ts tried for years in vain to repeat Til- 

 den's experiments, and if any firm, or any 

 chemist, did produce what he called artificial 

 rubber, the production was received with deep 

 suspicion rather than congratulation. In Janu- 

 ary of last year the indomitable Harries took 

 out a patent for heating '■isoprene" with strong 

 acetic acid in such a way that the desired 

 caoutchouc was produced— but it was nearly as 

 precious as rubies. What, therefore, was wan- 

 ted — perhaps we should say is wanted — was 

 cheap "isoprene." Now there is another vary 

 common hydrocarbon, whose molecule, com- 

 bining ten atoms of carbon with sixteen atoms of 

 hydrogen, is clearly indicated as the suitable 

 parent of "isoprene," It is oil of turpentine. 

 The problem of altering O10 H16 into C5 H8 is 

 therefore the real problem of artiiicial rubber. 

 We can put it much more lengthily by saying 

 that it may be done rather after the following 

 way. Oil of turpentine contains pinene. 

 Pinene heated, gives dipeutine. Standinger and 

 Kleven, by heating dipeutine in a partial 

 vacuum, have extracted "isoprene." " Iso- 

 prene" heated with strong acetic acid gives rub- 

 ber. Cheapen the process at all or any of these 

 stages and the trick is done. — M. Post, Nov. 3. 



MANURING FOR RUBBER. 



The Department of Agriculture has recently 

 been asked by a number of planters to advise as 

 to what manures to apply to rubber trees and in 

 what quantities they should be used, On the 

 majority of plantations it is doubtful whether 

 any manuring is required. There are a num- 

 ber of places, however, where the growth or the 

 general vigour of the trees is not equal to that 

 on others. In these places, provided it is not 

 the cultivation or the drainage that is at fault, 

 manuring may prove of advantage. Cultivation 

 in most places will be found of greater advan- 

 tage than manuring. If every rubber field could 

 be changkolled twice a year or receive an equi- 

 valent cultivation with ploughs, disc harrows, 

 etc., it is certain that both trie immediate and 

 permanent benefits would be great. Of course 

 with old trees which have formed an interlacing 

 root system near the surface of the soif such 

 cultivation would be dangerous, but with young 

 plantings cultivation is strongly recommended. 

 On fairly fiat lands which have been thoroughly 

 cleared of timber and stumps, probably 

 mechanical cultivation by ploughs or disc har- 

 rows will be found more economical and more 

 effective. The following recommendations for 

 manurial treatment have been drawn up by Mr 

 B J Eaton, Agricultural Ohomist, Federated 

 Malay States, It must be borne in mind that 

 they are based on general principles and are 

 not the result of experiments, Manurial. experi- 



ments have been started by the Department of 

 Agriculture, but reliable results will not be 

 obtainable from them for some years. It is 

 proposed to publish similar notes for other 

 types of soils. 



Manurial Treatment for Para Kubber on 

 Heavy Clay Soils. 



The following treatment is to be recommended 

 for clay soils : — 



fclaked lime ... £ to 1 ton per acre 



Basic blag (phosphate 

 manure) ... 350 lb. do 



Ammonium Sulphate 150 lb. do 



Potassium Sulphate... 100 lb. do 

 The lime and basic slag should be applied 

 about a month or two months before the other 

 manures as they decompose Ammonium Sul- 

 phate. The Ammonium Sulphate and Potassium 

 Sulphate should be mixea together and then 

 mixed with earth and subsequently spread, if 

 concentrated manures are used they frequently 

 injure the roots with which they come in 

 contact, and the earth is added as a diluent. 

 With trees one or two years old it is preferable 

 to dig a shallow trench (4 to 6 inches deep) at a 

 radius of 2-3 feet round the tree, sprinkle the 

 manure round and subsequently cover with earth 

 again. With older trees, where the roots in- 

 terlace, the manures may be broadcast and the 

 wholo surface forked over. 



The following can be used in place of Ammo- 

 nium Sulphate : — 



Castor seed cake, or 



Linseed cake, or 



Cotton seed cake or 



Para seed cake, or 



Ground-nut cake. 

 These should be applied at the rate of about 

 600 lb. per acre. If it is found that the cost of 

 the quantity recommended is cheaper than 

 the Ammonium Sulphate, I would recommend 

 their use. Instead of Potassium Sulphate may 

 be employed. 



Kainit(12 per cent Potash) 400 lb. per 



acre, or 



Potassium Chloride 100 lb. per acre. 

 The cost of the above quantities should be 

 compared with that of 100 lb. of Potassium 

 Sulphate, Instead of Basic Slag, Pedis Guano 

 or other Phosphatic Guano may be substituted. 

 Perils Guano (containing 15 per cent Phos- 

 phoric Acid) at the rate of 500 lb. per acre, 

 should be very economical, as its price is only 

 $25 per ton. In the first instance as a trial 1 

 would suggest the use of the most economical 

 fertilizer, until more is known of the different 

 effects on the Para rubber tree on different soils 

 of the various nitrogenous, phosphatic or 

 potash fertilizers. The average cost per acre 

 of the above formula excluding lime, will 

 amount to $20 to $25 per acre. This does not 

 include transport, freight or labour. Lime can 

 be purchased at SO cents to $1 per picul. 



L. Lewton Brain, 

 —Agricultural Bulletin, No. 11 for Nov, 



