Vol. XVII. No. 4:24. 



THE AGRICULTUBAL NEWS. 



23 J 



Mr. A. B. Carr, of Caparo, planted on i-acre 

 250 ib. of yams in well prepareil trenches, and veapeil 

 .5,030 It). The total expendiime was ,"!<1950, being 

 $7'50 cost of yams for planting, and .'<1200 cost of 

 cultivation The \ alne of the crop at oc. p'-r tb, was 

 !?1.50f»0, showing a profit on the i-acre of sl.Sl^O. 



On a similar small plot Mr. W. S. E. Barnardo, of 

 Tamana, with an expenditure of iSlSTO on cultiva- 

 tion, obtained crops to the value of .'*8()'45, leaving 

 a net profit of Stj7'7.5. Mr. ftarnardos crops were the 

 following: 3,090 lb. Lf yams at 2c. per tb.; 200 lb. of 

 Chinese tannias at Ic. per lb.: 1(>(» lb of cush-cush 

 at 3c. per lb.: I(i.5 lb. of pumpkins at Ic. per lb. 

 Mr. Barnardo states that the yam crop was poor 

 compared with that (if the previous season, owing to 

 e.xcessive rain in May and -lune. 



As an example fjlso of the way in which ground 

 provisions may be profitably cultivated on larger areas, 

 the following is the result obtained by Mr. L. Seheult, 

 River estate, Department of Agriculture, in growing 

 catch crops, mainly in establishing permanent cultiva- 

 tion of the following plants: 500 limes, 100 mahogany, 

 4,000 cedar, S,000' coffee. He reaped 19,000 tb. of 

 yams worth S54-0, at 2J,c. to 3c. per tb.: 72,000 lb. 

 of tanias worth SI. -1,40, at 2c. per tb.; 100 barrels of 

 corn worth S175, at !5l'75per barrel; and -SlOO worth 

 of ca.s.sava, peas, ochroes, pumptvins, and cucumbers: 

 makirg a total return of S2,2-')-"), at an expenditure 

 of $1,100, showing a net profit of SI, 155. The above 

 expenditure included the cost of planting and cultiva- 

 tion of the permanent crop, but not the cost of the 

 plants themselves. 



!■ I im 



Forestry in Trinidad. 



In the eilitoriai in the last number of this Journal, 

 reference was made to the fact that in Trinidad alone 

 of these West Indium islands was forestiy being carried 

 out on scientific lines. In the Proceedings of the 

 Agi-'i cultural Society of Triviihid and Tohago, May 

 191fS, the following figures, taken from the Report of 

 the Forest Officer for the year 1!I16, are given of the 

 number of the principal specits of trees which are 

 being grown in the forest plantations There are; 

 02,993 cedar. 42,355 cypre, 10,325 balsam, and 14:353 

 teak trees growing in the plantations at present. The 

 Forest Officer states that the trees aie not less than 10 

 feet apart, and that, including other valuable species, 

 there are over 140,000 trees in the plantations. 



The East Indian teak (Tectona grandis), the seeds 

 of which were obtained from Burma in 1913, continues 

 to do well. Many of these trees have now attain; d 

 a height of from 40 to 50 feet, and a girth of 2i feet 

 at 5 feet from the ground. The Forest Officer thinks 

 that the growth of the teak in Trinidad is equal to 

 that in any part of the world, and some 4,000 seeds 

 collected in the last year will be further sown in the 

 plantations. In each locality where these trees are 

 planted, the original forest containing.no marketable 

 timber of any consequence, was felled. . burnt, and 

 lined out with stakes at 10 fert by 10 feet. 



It is estimated that the yield in 100 years will b;; 

 240 tons of about 50 cubic feet of first class wood 



per acre, the present price of which is £50 per too, 

 although the normal pre-war price averaged t'2.5 

 pm- ton. Teak is one of the most valuable timbers, 

 much employed in shipbuilding, and for other purposes 

 where durability is required. 



Are Anopheles of Non-Marslay Districts Cap- 

 able of Transmitting Malaria? 



In a notice of an article by .M. E Eoubaud in Oomp- 

 t.cs Renclus des Seances cle I' Academie des Sciences, 

 September 17, 1917, published in the Agriculturat- 

 Gazette of Canada, May 191S, the result of the author'* 

 personal investigations of the subject is given. 



It is stated that in spite of the continuous presence 

 of Anophxles maculi^^ennis in certain reclaimed dis- 

 tricts of France which were previously marshy, malari^^ 

 has not reappeared to any marked extent. This factv 

 has given rise to the supposition that the extinc- 

 tion of the disease may be connected with a sortw 

 of natural immunity of the mosquitoes concerned To- 

 settle the point, patients under treatment for malaria as. 

 the Pasteur Institute at Paris were caused to be bitten 

 by perfectly healthful anopheles taken in the town, and 

 it was proved that these mosquitoes were infected with 

 the malarial parasites. The author, who was perfect- 

 ly healthy, then allowed himself to be bitten by one 

 of the infected mosquitoes. Fifteen days afterwards 

 the fever appeared, preceded a few days previously 

 by exhaustion: on the next day the sporazoito'i 

 which are known to cause tertian malaria fe\er 

 were located in his blood. 



It is therefore ivident that A nopheles micidi- 

 pennis of the Parisian non- marshy districts is in n'> 

 wise an immune species, and is perfectly capable of 

 transmitting malaria. It is indeed highly improbable 

 that any such immune species of a:iopheles exists. 



Rubber Substitutes. 



An article in the India Rabher World, .July I, 

 1918, by M. Andre Du Bosc, a distinguished French 

 chemist, on the prepiiration of rubber substitutes, giveg 

 much information on the subject. 



The action of metalloids like oxygen and sulphur, 

 of certain chlorides like chloride of sulphur, and of 

 acids like nitric acid, on vegetable or ammal oils, pro- 

 duce new bodies of which the physical and chemical 

 properties differ absolutely from the oleaginous sub- 

 stances from which they have been derived. Because 

 of their physical resemblajice to rubber, these p.'od'icts 

 are called rubber substitutes. 



The chemicals most frequently employed in pre- 

 paring commercial rubber substitutes with differenr. 

 kinds of oils are sulphur, and chloride of sulphur 



In principle, all vegetable or animal oils luay b-:^ 

 used: nevertheless experience has proved that certaiu. 

 drving oils like th:it from linseed are preferable How- 

 ever. ni>ii-ilrying V'?get ible oils like c-istor oil may also 

 give an exc -llenc robber substitute. Finallv ^"'ir-p th^ 

 war. fi^h oils hnve al.«o be^h used. 



