as you would tip a dray, and down goes Mrs. Blue-bottle head first, her wings jammed close against the pillar between the two flanges, and her back just touching the edge of the pollen-cap, a front view of which may be seen to the right of the illustration near the top. Then begins a struggle. If she is a small weak fly, as many here are, she never escapes at all, but perishes miserably, and is quickly devoured by the small ants, and the wings sticking against the concave sticky face of the pillar show that many such tragedies have occurred, as is also shown by the presence of the dead flies. But this is not what the orchid wants. It has no use for dead bluebottles. It wants them as slaves, but not as provender. But, see, here comes a large strong fly; she alights on the platform, walks up to the balance, and is tipped down the cavity. But she will not perish without a fight. Step by step she works back, forcing herself against the pillar, and wriggling furiously. She catches the edge of the pollen-cap, forces it off; in a moment the pollenmasses, fresh and sticky, are fastened to her back; one supreme effort, and she is free and off with a glad buzz. But, sad to reflect, she has learnt nothing from the deception and narrow escape. In a moment she is back again, gingerly mounting another balance, which as surely tips up and jams the pollen-masses against the stigmatic surface of the flower, where they remain. The most skilful hybridiser with his camelhair brush could not have done it better. Then the struggle begins all over again, and the fly takes away another load of pollen, but leaves that which she brought from the former flower. It will be noticed on looking at the drawing that one flower-leaf stands above the balance, as we have called it; and on looking at the lower flowers, it will be seen that this leaf is closed down in some of them, like a lid. This lid is always closed before the pollen is ripe enough to be carried away; and when the pollen-masses have been deposited on the stigmatic surface, the lid again closes down, and remains so closed until the seed-vessel is formed and the flower withers: the presence of insects is no longer desired. We spoke of the intolerable odour of the living flower. Strange to say, the withered flower has a delicate perfume, exactly like that of newmown hay. Tropical Industries. SUGAR-CANE. In order to attain a luxurious growth, sugar-cane must be cultivated in a moist, warm climate, with short intervals of hot, dry weather, tempered by refreshing salt-breezes. Long periods of dry weather, and even passing spells of cold, are hindrances to successful growth. The soil should be calcareous, rich in humus, and somewhat loamy. Medium, easily worked soils are preferable to heavy, clay soils, and also to light, dry, sandy soils. A deep soil, with ready facilities for irrigation, is desirable. Sour soils, containing too much humus, may produce a vigorous growth of cane, the juice of which, however, contains but little sugar, and is difficult to An examination of the soil is, therefore, of the utmost importance; it should include the determination not only of the most essential plant-food ingredients contained, but also of the injurious constituents. When certain convert. salts, occurring in sea-water, are present in small quantities, they promote the growth of cane, without, however, exercising any beneficial influence upon the formation of sugar; when present in large quantities, these salts may prevent growth entirely. Dr. H. Winter* analysed two soils in Java, to determine their lack of fertility with respect to sugar-cane, with the following results:1. 100 parts air-dried soil contained The soluble portion, calculated to 100 parts dry soil (at 150 degrees C.), contains: 0.13 per cent. chlorine corresponds to 0.21 per cent. chloride of sodium, which is very high, because a soil analysing over 0.1 per cent. chloride of sodium is considered unfertile. 2. The second analysis concerned subsoil water with a higher percentage of chlorine, which also occasioned an inferior growth of sugar-cane, as can be seen from the comparison of two different waters 100,000 parts subsoil water from fertile field contained 72.75 parts chlorine 100,000 unfertile, 336.50 وو A portion of the chlorine is absorbed by the plant, and acts injuriously upon the formation of sugar; as a consequence, the cane grown in the salty underground water contained but 9.8 per cent. sugar, only 764 per cent. of the juice being pure. The ash of this cane contained a very high percentage of chlorine. According to the examinations of Professor Stutzer, of Bonn,† diseased, in comparison with healthy cane, analysed as follows: One hundred parts of dried cane at 100 degrees C. contained— The minimum quantities of various plant-food ingredients essential for a good sugar-cane soil have, with the exception of lime, not as yet been determined. Semmler‡ states that the soil should contain at least 1 per cent. of the latter constituent. Nitrogen, phosphoric acid, and potash should be applied artificially in almost every case, as the supply of these ingredients in the soil soon becomes insufficient for the needs of the crop. Sugar-cane requires a considerable amount of the essential plant-food ingredients, as shown by the detailed investigations of Mr. C. J. van Lookeren, of Campagne Klatten.§ This gentleman found that a crop of cane removed from one acre: Archief voor de Java-Suikerindustrie, 1894, I., pag. 129 + Landw. Versuchsstationen, 1892, p. 325. +++:00 Semmler, "Die tropische Agricultur" III., p. 224. It is evident that even the best soils will become depleted in the course of time, and they must, of course, be replenished, in order to produce profitable crops. The continued planting of sugar-cane exhausts the soil very rapidly, causing first a deficiency of nitrogen, then of phosphoric acid, and lastly of potash. The application of stable manure and artificial fertilisers is, therefore, rendered indispensable. Unfortunately, ready mixtures are generally applied to this plant, so that only by conducting exhaustive experiments can we obtain definite results regarding the beneficial effects of the single ingredients. A few trials have been inaugurated, it is true, but no fixed conclusions can be drawn from them. The following three tables, illustrating the results of the latest experiments conducted in Java, were recently prepared by Mr. W. Eicke, Mestfabriek, Samarang : FERTILISER EXPERIMENT ON SUGAR-CANE IN JAVA. |