Vol. XIII; No. 309. 



THE AOPJCULTFRAL NEWS. 



73 



year under review, together with those of former ones, 

 indicate that the addition of artificial manures under 

 conditions existing nt La (iucrite (the Experiment 

 Station) has not been attended with remunerative 

 leturns". The writer maintains, apparently from 

 practical experiei ce, that the reason for the unbene- 

 ficial results lies in nothing more or less than the 

 circumstance that the fertilizers have not been applied 

 in the proper way. The correspondent states that the 

 method employee! of sowing the manures in drills 

 which consists in opening the soil around the plant 

 on the side of the cross-hole to the depth of about 

 li-incbes, and sprinkling the fertilizer around the plant 

 in these drills and then covering them with soil, is 

 wrong. It is mamtained that the root system of the 

 cotton plant in St. Kitts is essentially deep rooting, 

 and this circumstance together with the belief that 

 the manure being so near the suface is soon removed 

 b}" the labourer's hoe at weeding time, are put forward 

 as indicating the inefficiency of the method just 

 described. 



As a matter of fact an extensive study of the root 

 system of the lotton plant in St. Kitts has shown that 

 the lateral root system which spreads more or less 

 horizontally in the light, sandy soil is developed to 

 a greater extent than the tap root: hence the plant is 

 to be regarded as comparatively shallow rooting com- 

 pare with cotton plants growing in stiff soils like those 

 of Antigua. This would appear ti> be a point in 

 favour ot the shallow application of fertilizers or rather 

 a point in favour of broadcasting. 



The writer also states that a different procedure 

 is followed in the Southern Siiates of America, but be 

 does not say how this diHi'rs from the method adopted 

 in St. Kitts, nor whether it would be practicable to 

 introduce the method. 



In looking up several references on the point 

 we find it stated in one of the cotton pamphlets 

 of the Khedivial Agricultural Society that when 

 the manure is large in amount, no advantage is 

 to be gained by spreading in the drill com- 

 pared vviih broadcasting, but when the cjuantity 

 is small there is an advantage in spreading it 

 along the bottoms of the furrows. Again in the 

 I'nited States De]partment of Agriculture Bulletin No. 

 33 on the Cotton Plant, the best mode of application of 

 fertilizers is summed up as follows: 'Fertilizers may be 

 indifferently drilled or broadcasted where they are 

 liberally supplied, but drilling is to be [preferred where 

 small amounts are employed.' Similar views are 

 expressed in (.'. H. Birkett's book on cotton. Since 

 large quantities were not used in the St. Kitts experi- 

 ments there would seem to be something perhaps in 

 the suggestion that the manures ought to be put in 

 more deeply. 



In considering the subject broailly it must be 

 confessed that the letter which is responsible for this 

 article has raised a question which ought to receive 

 careful consideration, and it would be interesting if 

 trials could be maile with manures supplied to plots in 

 equal (piantities but in different ways. It is worth 

 while, in the present connexion, however, to bear in 

 mind that last year for the first time the application of 



manures at La Guerite gave an increased yield which 

 would seem to show that the unbeneficial action in the 

 past has been due to chemical rather than mechanical 

 causes. ^loreover in former years the application of 

 manures at La Guerite to cotton has actually decreased 

 the yield in certain cases. If, as is suggested in the 

 letter, the manure is removed by the weeder's hoe, 

 how is the effect on the crop just described to be 

 accounted for' 



Turning Liiquid Oils into Solid Fats 



The far-reaching importance of any economical 

 method of converting a liquid oil such as cotton-seed 

 oil into a solid fat (of w'hich palm oil is an example) 

 can be readily realized when the prices of the two 

 classes of compounds are compared. The subject has 

 received considerable attention of recent years and 

 lately an article on the subject has appeared in the 

 Jh.dletbi of tlie Imperial Institute (October-December, 

 1913) which shows that the success which is attending 

 a new process now in vogue is likely to result in the 

 lowering of prices of certain of the harder natural 

 fats, for example palm kernel and coco-nut oils. 



Without going into the chemical details of the 

 reaction tuo closely, it may interest the general reader 

 to know that the essential feature of the process is to 

 convert oleic acid (which is the chief compound in 

 licpiid oils) into stearic acid (which is found in solid 

 fats). The change is brought about by the simple 

 process of reduction (i.e. the addition of hydrogen, 

 hence reduction in the percentage of oxygen) accord- 

 ing to the following equation: — 



C,, H,,4 O, -I- H., = CisH.i^O, 

 ( lleic acid. Hydrogen. Stearic acid. 



It appears that the conversion of 2,000 tb. of 

 oleic acid into stearic acid would require about 14 tb. 

 or 2, .500 cubic feet of hydrogen gas. It may be added 

 that in the course of the reaction the presence of 

 ,1 catalytic agent is required to facilitate the change. 

 (The catalyst is not affected by the reaction.) 



We may end this brief note by quoting a few 

 of the conclusions arrived at by the Imperial Institute 

 in regard to the subject under consideration. 'A poss- 

 ible effect that at once suggests itself is the lowering 

 of prices of certain of the harder natural fats, e.g. palm 

 kernel and coco-nut oil?, which are largely used in the 

 manufacture of edible substances, while the demand 

 for liquid oils which lend themselves readily to the 

 process of hardening may reasonably be expected in- 

 crease with a corresponding increase in value 



Liquid oils can be purchased at as low a price as £17 

 per ton for .Tapanese fish oil. It should therefore be pos- 

 sible to produce from this material a hardened oil which 

 should beat least equal in value to low grade palm oil, 

 namely £2(i per ton at a cost of about £22 per ton. 

 The tact that numerous firms of oil manufacturers are 

 interesting themselves in this process is sufHcient to 

 show that it is regarded as likely to prove profitable.' 



It is yet too early to prognosticate, but an exten- 

 sion in the employment of the process may be reason- 

 ably exjiected to affect favourably West Indian cotton 

 yrowers. 



