s68 



THE TROPICAL AGRICULTURIST. 



[September i, 1882. 



The fixing of ammouium carbonate rests solely on a 

 cliemical process. The cliauge therefore takes place with 

 greatest perfection when insoluble carbonates are formed. 

 The length of time of action of the salts on one another is of 

 a very small importance, as regards the quantity of ammonia 

 fixed. The following numbers illustrate this fact. They 

 represent the fixed ammonia in percentages of the entire 

 quantity of ammonium carbonate present in the mixture. 

 The mixture A^as gyjisum with 10 per cent of ammonium 

 carbonate; — Immediately, 53"50 percent; after twenty-four 

 hours, 60"00 per cent; after forty hours, 61'50 per cent; 

 after 120 hours, 7-i'30 per cent. For jiractical purposes, 

 we may deduce from these experiments that gypsum and 

 magne.sium chloride are by far the most suitable for the 

 prevention of the volatility of ammonium carbonate; but 

 magnesium sulphate, kaiuite, and kieserite are also useful 

 for this purpose, and, therefore, where they can be obtained 

 easily and cheap, they may be used to advantage. Special 

 attention is due to magnesium chloride, because of its 

 very low price. With regard to the objection that, when 

 magnesium chloride is used, chlorides are added to the 

 soil which are injurious or even poisonous to plant life, 

 the author refers to his work, " Potassium Salts and their 

 Application iu Agriculture," where there are facts which 

 show that, in many cases, impure potassium salts (contain- 

 ing chlorine) have produced larger results than the pure 

 salt not containing chlorine. — Field. 



OXTLTIVATION OF USEFUL PLANTS IS SAN 

 DOMINGO. 



In a recently issued report by Major Stuart on San 

 Domingo it is stated that the cultivation of the Sugar- 

 cane may now be considered an established industry in 

 the district of Porto Plata. There are already five large 

 plantations in bearing, with mills of the most approved 

 construction. The area of many of the old plantations is 

 being enlarged, and new ones are marked out for immediate 

 clearing. The cultivation of the Sugar-cane is, however, 

 ont the only agricultural industry that has lately begun 

 to flourish in this district; Oocoa, Ooffee, and Tobacco are also 

 produced in continually increasing quantities, having each 

 a good surplus for exportation after liberally supplying. the 

 home trade for local consumption. Previous to the recent 

 introduction of the Sugar-cane, Oocoa, Ooffee, and Tobacco 

 formed the staple produce of the country, and its chief 

 medium of commerce. About 12,000 quintals was annually 

 exported, nearly all of which was sent to Bremen, the 

 chief market for the produce of Porto Plata. In 1S78 or 

 1879 the consignees at Bremen wrote to their correspond- 

 ents in Porto Plata th.at they would accept no more consign- 

 ments of Dominican Tobacco, as owing to the want of 

 proper care in the cultivation of the plant, and in the 

 preparation of the leaf, it could not be sold unless at a 

 heavy loss. This announcement produced a widespread 

 consternation in the country, for it seemed to threaten 

 both growers and exporters with ruin. Happily the remedy 

 was at hand. A good many Cubans were in the country 

 who understood the Cuban mode of cultivating and pre- 

 paring Tobacco; they were appHed to by the Dominican 

 growers, and the truits of their instructions were the ex- 

 portation from Porto Plata alone of 40,000 quintals iu 1880, 

 and 100,000 quintals in 1881, of prime Tobacco. 



Dominican Tobacco is now in demand, at good prices, 

 not only in Bremen, but also in Liverpool, Havre, and New 

 York. Its cvltivation is carried on in the southern districts, 

 -as well as iu the north, and on a yearly increasing breadth 

 oif laud, while both in the north and south factories are 

 already establi.shed for the manufacture of cigars and ci- 

 garettes under the superintendence of Cubans of experience. 

 Of these manufactures there is already a very considerable 

 exportation, with every prospect of increase. In faet the 

 Dominicans aim at competing with the Cubans in the 

 finer sorts of Tobacco, and as they possess the same ad- 

 vantages of soil and climate, there is no reason why, with 

 equal skill and care, they should not succeed. 



Major Stuart further writes as follows: — 



"All that I have said .about the progress of agriculture 

 in the north applies in every particular to the south, but 

 in a much larger sense :i-; regards Sugar. On the lands 

 lying aback from the capital, and along the b.anks of the 



lower Ozama, numerous cane plantations are now e.stabhshed 

 each complete with mill and all the stock and require 

 ments tor the production of sugar. There are already 

 twenty-three of these plantations within a racUus of a few 

 miles round San Domingo city, and it is not intended that 

 the number should rest there. When I visited San Domingo 

 for the first time, in the fall of 1875, none of these 

 plantations existed, but one — the first iu the country — was 

 in course of clearing, and workmen were engaged in putting 

 up the mill. Last year, I may add, a system that promises 

 well was tried of inducing small holders in the neighbour- 

 hood of plantations to raise canes on their lands, anil sell 

 them in a raw state to the millowners. The cultivation 

 of Ooffee is also in a promising condition iu the Dominican 

 country. Oongenical soil and climate for it are found 

 without difiiculty in v.arious xjlaces, but chiefly at present 

 on the heights above Azua overlooking the Bay of Ochoa, 

 a deep inlet that thvides into nearly equal p.arts the south 

 coast of the island. Here a shiall Coft'ee plantation was 

 established in 1877 by President Gonzalez on his patrimonial 

 lands. It succeeded so well that others hastened to follow 

 the example, not only in the neighbourhood of Azua, but 

 also in different parts of the country. The little tree is 

 tended and dressed with proper care, the berry is treated 

 after the most approved process, and so rapidly has the 

 cultivation extended that even now Dominican Coffee appears 

 in its own name on foreign markets, and is quoted, I have 

 been told, on a par with that of Jamaica. The quantity 

 exported is still compariitively small, but it increase.? with 

 every season. Until 1878 Ooffee was imported into the 

 country, for the Dominicans are a coffee-di'inking people, 

 and now it is the siuplus left after the supply for home 

 consumption that is sent out of the country." 



The next production to be noticed is the Cacao or Choco- 

 late tree. This tree is of recent introduction into the 

 Dominica country. It has taken very kindly to the soil, 

 and being cultivated with care it yielils abundantly, and 

 the kernel is of good quallity. Cacao now figures well among 

 the exports of the country, with an annual increase which 

 keeps pace with that of Sugar and Ooffee. — Gardeners' 

 Chronicle. 



MANURES AS ABSORBENTS OF WATER. 



BY A. STEPHEN WILSON. 



I am not aware that any complete theory of a mamu:e 

 has yet been laid down ; nor I do propose entering upon 

 the labour of laying down such a theory. My present 

 purpose is to show, from experiments made by me, that 

 manures perform a certain office in addition to that of 

 directly supplying plants with the food contained in tkeir 

 own substances. The office to which I refer is that of 

 absorbing moisture from the atmosphere — a function which 

 may be called hygrosorption (huffros, moist, and sorbeo, I 

 drink up). Now, it would seem obvious that if iu ft 

 dry season a given manure has the capacitj' of abiorbing 

 moisture from the atmosphere more copiously than the 

 soil iu which it is mixed, the roots of plants growing in 

 that soil and manm-e will be better supplied with water 

 than if the manure were absent. And if, of two manures, 

 the hygrosorptive power of the one is greater than that 

 of the other, a plant growing in the more hygrosorptive 

 will be better supplied with water than a plant growing 

 in the less. But the results will be better seen after the 

 experiments have been detailed. 



Some trials of a rough kind were first made in search 

 of suggestions. Two small flower-pots were filled with soil ; 

 two were filled with the same soil mixed with finely ground 

 Cambridge coprolite; two with .soil and dissolved coprolite; 

 and two vrith soil and guano. The pots were accurately 

 weighed and set beside each other iu the evening in a 

 garden walK. In the morning it was found that the soil 

 alone had gained 47 grains; soil and ground coprolite, 42 

 grains; soil and dissolved coproHte, 60 grains; and soil with 

 guano, 54 grains. This comparison was carried on for 

 twelve days; but the conditions were seen to be very 

 defective. The pots were of equal size, but possibly varied J 

 in porosity. The sriil and the manures at the outset were i 

 just taken as they c:;me to hand, and therefore may-have | 

 contained, to being with, varying percentages of moisture; 1 

 then slight showers occa.sionally fell, while the wind may ] 

 have carried off from some of the pots a few particle 



