Vol. XIII No. 306. 



THE AORICULTURAL NEWS. 



31 



were practically worthless are now bearing phenomenal crops. 

 It has, moreover, been found possible to reclaim swampy land 

 and to drain swamps by blasting the impervious clay beneath 

 them; anad fruit growers in many instances use explosives in 

 preparing the ground for the planting of fruit trees. 



It is in breaking up 'hard pan' that the use of explosives 

 is expected to be of most service in the Federated Malay 

 States, and the following experiments were a very successful 

 demonstration of the effectiveness of Nobel's (of Glasgow) 

 gelignite for the purpose, even though the site chosen was 

 not the most suitable, being a very soft soil not particularly 

 in need of treatment. But in the Federated Malay Stites 

 as in other parts of the world, at a slight distance below the 

 ordinary open subsoil, a hard layer of clay or other practically 

 impervious subsoil is found, which acts as a trap for surface 

 water, impedes the growth of tree roots, and prevents them 

 getting the necessary sustenance. 



Later in a plantation of two-and-a half-year old rubber 

 trees, Mr. :MacQueen placed rows of gelignite* cartridges at 

 a depth of about ih feet below the surface, and fired them 

 by means of fuses and detonators. On the surface there was 

 little visible effect of the explosion, but when the soil was 

 turned over, it was found to be split and broken in all direc- 

 tions. The effect of each explosion is stated to be felt over 

 a circle with a radius of 12 feet, and is claimed to have 

 beneficial results over a period of two and a half to three 

 years. And all this at a depth which the coolie with his 

 changkol could not hope to touch. The inclusive cost of 

 boring, explosive fuse and detonator for each hole is at the 

 outside 13c , and the benefit to any plantation of a thorough 

 and comprehensive treatment by explosives is too apparent 

 to need explanation. 



Another use demonstrated during the trials was the 

 blasting of holes for planting trees. Half a cartridge was 

 exploded at a depth of 20 inches and when the top soil was 

 scraped off a cavity a foot in diameter was revealed. Of 

 course, what has been said above as to the benefit to the soil 

 in preparing it for the easier growtli of the roots applies also 

 in this case, while the whole process is much quicker and 

 handier than digging by hand. 



Yet another use is for felling. A large old jungle tree 

 ,was selected for the purpose, and eight cartridges placed in 

 the centre of the trunk at a height of about 5 feet from the 

 ground brought the tree down in a very small portion of the 

 time which would have been occupied in felling by ordinary 

 methods. 



On the question of time occupied in breaking up 'hard 

 pan" by explosive, or 'ploughing by dynamite' as it has been 

 picturesquely termed, Mr. Mac()>ueen stated that with two 

 coolies he bored holes for, and placed in position thirty cart- 

 ridges, ready for exploding, within an hour. The harder the 

 soil, of course, the more effect has the explosion, this method 

 having been used with most success in the case of laterite 

 soils. 



For removing stumps gelignite also has its uses, though 

 to be effective the bore holes must be made very carefully, for 

 in the Federated Malay States most of the trees are of the 

 'buttress' type, and it is at times, very difficult to judge 

 whether you are boring straight into wood, or out again into 

 the soil. However a large stump was very effectively shat- 

 tered this morning, showing that a very little work would have 

 removed the whole lot. So far as Malaya is concerned, 

 therefore, we feel that if the use of e-xplosives in agriculture 

 is new, it will soon become popular. 



*The City OHice of Tropical Life has on .show a case of 

 <lummy facsimiles of all these cartgidges, together with fuses, 

 wires, detonators, etc., the whole forming a complete outfit. 



ZOOLOGICAL 



WEST INDIAN ARMADILLOS. 



Headers of the Agricaltiiral Netos will be interested to 

 learn that Dr. A. H. Clarke, of the Smithsonian Institution, 

 United States National Museum, is publishing in the 'Annals 

 and Magazine of National History' a paper in which he is 

 recording from the island of Tobago, the Grenada dwarf 

 nine banded armadillo, Deaypia novemcinciuf hojdites, and 

 the Trinidad mouse opossum, Manuosa. 



Armadillos were first reported from Tobago in 16-58 by 

 C. de Bochefort. who remarked upon the small size of the 

 local form; but no definite record of the species inhabiting 

 the island has heretofore been published. In Grenada 

 armadillos have been known to occur since 1667, in which 

 year they were reported as common there by Pere du Tertre, 

 who also mentioned that all attempts to introduce them into 

 other of the (then) French islands had met with failure. 

 During a visit of some weeks to Grenada in 1901, Dr. Clarke 

 found that armadillos were not at all uncommon there, though 

 he did not succeed in securing any specimens. For some years 

 the local form had been regularly recorded in the 'Grenada 

 Handbook' under the name of Basvpus noveincinctus. In 

 a paper published in 190.5 ('The Auk', Vol. 22, July 1905. 

 pp. 270 and 271) Dr. Clarke wrote 'To-day Grenada is the 

 only island (except, of course, Tobago and Trinidad) where 

 the armadillo is found,' and remarked that it was still called 

 there by the same name, Tatu, under which it was referred 

 to by du Tertre and Labat. In 1910 Dr. Glover M. Allen 

 visited the island and secured three specimens upon which he 

 based, in the following year, the name Dasi/jms novemcinctus 

 hoj'lit'-s. The typical form, Dasypus )weim:inctiis novemcinc- 

 tus, occurs in Trinidad. 



The Trinidad mouse opossum, 'manicou rat' or 'manicou 

 gros yeux', Marmosa chapmayii, occurs in Trinidad, Tobago, 

 Grenada, Isle Ronde and Carriacou. 



ECONOMIC VALUE OF THE BAT. 



According to the Review of Apjilied Entomology — 

 Series B: Medical and Veterinary, for October 1913, bats are 

 probably immune from the bite of a mosquito, firstly because 

 of the peculiar formation of the hair covering their bodies 

 and secondly because of their peculiar odour. Bats in general 

 are remarkably free from disease, and this is shown by the 

 fact that although they live in caves in vast numbers, touch- 

 ing one another and even hanging to one another, yet men 

 engaged in collecting bat guano very rarely find a single 

 animal dead. 



In Texas, experiments have been made with the object 

 of cultivating bats for the production of guano, and at the 

 same time for the control of mosquitoes. It has been found 

 that a structure large enough to hold 50,000 bats would cost 

 considerably less than £2,-t00 and that would yield in a year 

 2o' tons of guano of an average value of £121 10s. During 

 the experiments, enquiries made in the district, of the heads 

 of fourteen families, showed that the number of mosquitoes 

 had abated remarkably, and that the fever which was pre- 

 viously rampant had almost entirely vanished. It is there- 

 fore concluded that it is not only commercially, but hygen- 

 ically profitable, to cultivate bats. 



