April i, 1884,] 



THE TROPICAL AGRICULTURIST. 



729 



ation, there would seem to be no need for further 

 experiments at the public cost. 



Finally came the order of Government : — 

 The Government observe that the young Castilloa and 

 Uetca plants received from Ceylon arc doing reuiarkably 

 well on the whole under tlio intelligent care of Mr. T. J. 

 Ferguson, and that propagation from these plants may 

 shortly be expected to commence. It would seem from 

 the Collector's letter tliat Mr. Ferguson has expressed a 

 wish to hand over the further conduct of the experi- 

 ment to the Forest Department, but the Conservator rightly 

 points out that wiiile there can be no objection to the 

 mailing of small experiments at Nilambur, Manautoddy, 

 and Chenat Nair, under the direction of the local forest 

 officers, it would at present be impossible for the depart- 

 ment to spare the time required for the conduct of direct 

 operations on anything like a considerable scale. While 

 fully concurring in this view, the Government think it very 

 desirable to proceed at once with an experiment which 

 has been so well begun, and would much prefer to make 

 no change whatever in the existing arrangements unless 

 compelled to do so. The Collector will therefore be re- 

 quested to communicate further with Mr. T. J. Ferguson 

 and to arrange, if possible, for a continuance of the ex- 

 periment on its present satisfactory footing. Meanwhile 

 steps will be taken to obtain more plants, if procurable 

 from Ceylon, and the attention of the Director of Gov- 

 ernment Cinchona Plantations, Parks and Gardens. Nil- 

 giris, will be drawn to the omission of the Curator, Ootaca- 

 muud Government Gardens, to supply Jpecaauinha plants, 

 as promised, either to Mr. Ferguson or to the District 

 Forest Officer at Manautoddy. Mr. Lawson will also be 

 requested to report his views as regards the suggested est- 

 ablishment of a forcing-house and nursery at Calicut. 



As regards the Calisaya and other varieties of cinchona, 

 the cultivation of both red and yellow barks is reported 

 to be so well established now in South Wynaad that, 

 in the opinion of all concerned, further Sta*e experi- 

 ments are unnecessary. The experiments already commenced 

 will therefore be discontinued, and the Conservator will 

 advise as to the best method of disposing of the plants 

 of Government now under Mr. T. J. Ferguson's care. 



It would seem, therefore, that, while the cultivation 

 of rubber-yielding plants is still in the initiatory 

 stage in Wynaad, all the leading sp cies and varieties 

 of cinchona are grown largily and successfully, ex- 

 cept C. carthaiji'na. which does not seem very promis- 

 ing. While dealing with cinchona culture we may 

 mention what a planter mrntioned to us in regard 

 to cinchonas planted amongst coffee and growing so 

 luxuriantly as to prevent the latter from bearing. 

 Now that the cinchona have been cleared oat, the 

 coti'ee tlouri.-hes not merely in proportion to the bene- 

 fit derived from the removal of its lival, but from 

 the long rest it received while kept in the shude. 

 Such bushes are likely to he more vigi rous, he believe', 

 and to bear better crops than those grown in tli** 

 open and putting on regularly their full crops of 

 foliage only to be attacked virulently by leaf-disease. 

 We should like to hear the opinions of other planters 

 on this matter. 



CROP-MANURES. 



It is certain that we are becoming better acquainted 

 with the action of manures, and know now how 

 to apply thini to special crops with expectations 

 of obtaining ilie best results. Professor Atwater's 

 views correspond with those we entertain, .nnd they 

 have been formed from experimental observations and 

 researches extending over a quarter of a centurj'. 

 Corn need little nitrogen beside what it can draw 

 from natural sources, while its yield is largely in- 

 creased uuder the influence of miueial fertilizers ; 

 the most effective being those in which the cliiif 

 oppo out is phosphoric aciil. or potash according to 

 tne soil and the season. Potatoes respond uniformly 

 t> all the fertilizing ingredients, and they are less 

 able than corn to gather from natural sources, The 



ya 



same appears to be true for turnips. Not enough ex- 

 periments have been made with other crops to justi- 

 fy conclusions concerning them. Piactically the 

 largest yield for all crops is secured by the use of 

 fertilizers conlaining all the essential elements of plant- 

 food. Used alone, nitrate of soda is rarely useful, 

 sulphate of lime frequently, muriate of potash very 

 often, and the superphosphates generally. Soils vary 

 in their capacity for conveying food to crops, and 

 careful observation and experiment are neces-'ary to 

 determine the needs of a particular soil. — Popular 

 Science News. 



EMULSIONS OF PETPvOLEUM AND THEIll 



VALUE AS INSECTICIDES. 



By C. V. BiKLEY OF Washinoton, d. c. 



The value of petroleum for the destruction of in- 

 sects has long been reoogmzed, and I have for years 

 been endeavouring to solve the question of its safe 

 and ready use for this purpose without injury to 

 plants. This paper contains the resu.ts of extended 

 experiments carried on under my direction by teveral 

 of my assistants, and particularly by Profe-sor W. 

 8. Barnard, Mr. Jos. Voyle of Gainesville, Fla., 

 Mr. Clifford Richardson, assistant chemist of the De- 

 partment of Agriculture, and Mr. H. G. Hubbard, 

 who has for over a year been devoting his time 

 to practical tests in orange-groves at Crescent City, 

 Fla. 



Passing over the ordinary methods of oil-emulsions 

 by phosphates, lacto-phosphatcs, and hypophosphite 

 of lime, and various mucilaginious eubstauces, experi- 

 ence shows, that for the ordinary practical pur- 

 poses of the faimer and fruit-grower, soap and milk 

 are among the most available substances for the 

 production of pretroleum emulsions. Ordinary bar- 

 soap scraped and rubbbed into paste at the rate of 

 twenty parts seap, ten parts water, thirty parts kero- 

 sine, and one part of fir-balsim, wdl make 

 when diluted with water, an emulsion stable enough 

 for practical puiposes, as the slight cream which in 

 time rises to the surface or the flakiness that often 

 follows, is easily dissipated by a little shaking. 

 Soap-emulsions, are, however, lefs satisfactory and 

 efficient than those made with milk. Emulsions 

 with milk may be mide of varying strength ; but one 

 of the most satisfactory proportions is two parts of 

 refined kerosino to one part of sour milk. This 

 must be thoroughly churned (not merely shaken) 

 until a butter is formed which is thoroughly stable, 

 and will keep indefinitely in closed vessels, and may 

 be diluted ad libitum with water when needed foi- 

 use. The time required to bring the bu'^ter varies 

 with the temperature, and both soap and milk emul- 

 sions are facilitated t)y heating the ingredients. 

 Ordinary condensed milk may also b: used by thor- 

 oughly stirring and beating it in an equal or vary- 

 ing quant iiy of kerosine. 



The diluted emulsion, when prepared for use, 

 should be finely spr lycd upon the ins. cts to be killed, 

 its strength varying for different iisects or plants, 

 and its effect enhanced when broH^,ht forcibly in 

 contact with the insccti. 



Of mucilaginous substances, that obtninod from the 

 root of Zamia iufiip- /olin (a plant quite common in 

 parts of Florida, and frrm the stem- of which the 

 Florida arrowroot is obtained) has pioved useful as 

 an tmulsider. 



These petroleum -emulsions have broi used with 

 success by Dr. .J.C. Neal of Archer, !■ I», against the 

 cotton-worm, without injury to thopl. iit; but their 

 chief value depends on their etEoacy against the 

 differel scale-insects which effect citnn plants. Ex- 

 perience so far shows that tuch plants do noteutier 



