February i, 1883.] 



THE TROPICAL AGRICULTURIST. 



691? 



sharp showers of rain wash the gravel clean and bright. 

 The preventive action of salt is only good for about 

 three or four months, vegetation reappearing in perhaps 

 an aggravated amount on damp or shaded walks. As 

 yet the duration of the preventive action of the acids 

 has not been fully determined, but the garden superin- 

 tendent has marked on a plan the walks as severally 

 treated, and the Fellows of the Society and visitors to 

 the garden will be enabled to judge the relative values 

 of the agents. The liquid compounds were spread over 

 the walk by the ordinary watorpots with tin roses. Lead 

 or pewter would be better ; zinc must not be used. A 

 rose made of thin sheet German silver resisted the actiou 

 of the sulphuric acid well. For the distribution of the 

 salt I constructed a special machine. It consists of a 

 square box sieve of perforated zinc mounted on wheels 

 with an automatic action, so arranged as to communicate 

 to the sieve a jolting motion when drawn along tlie walk. 

 The wced.s on the walks consisted of grass, spergula, and 

 small varieties of moss, &c. From time to time I will 

 report the result of the experiments, and shall be happy 

 to make trial of any other agents recommended— W. 

 SOWEKBY, Secretary." — Adelaide Ohsei-ver. 



ON THK ECONOMIC VALUE OF THE 



JAK TREE. 



[We commend the foUomng article from the Intlian 

 Aqricullurist to the attention _of our readers, some of 

 whom may be able to add Information regarding the 

 fniit, the indiarubber-like juice, the timber, &c. We 

 believe large jak trees sell up to RlOO each in Ceylon 

 for canoes. — Ed.] 



Natural Okder — AHocarpacee ; Artncarpns inlegri- 

 folius. Known in Bengal as the — Kanlhal. 



Although this is tree that is grown near to every 

 rj'ot's honse in Bengal, and in fact can be grown on 

 almost any soil, provided the climate is not a very dry 

 one, its value has, I believe, never been fully tested, 

 and these lines are written with the view of attracting 

 attention to it. 



Belonging as the jack does to the bread-fruit older, 

 its growth, in a climate «nd on soil where the bread 

 fruit grows, is only a natural arrangement, and there is 

 little doubt but that the jack trees in Ceylon are about 

 the finest one can see. 



The jack tree is grown meiely for its fruit, which all 

 residents in India are aware is very large, very luscious, 

 and has a very strong smell of uver-ripe fruit which 

 very few Europeans can appreciate, but which the 

 natives revel in. 



The wood of tlif jack tree is very like the mahogany 

 in " £;rain," and were it not for its bright yellow colour, 

 it would be a great favourite with cabinet-makers. As 

 itie, jack wood is used largely for all domestic furniture, 

 and when put thrnugh a process of staining, is greatly 

 admired and always commands a ready sale. The jack 

 trees in Bengal do not grow lofty, but they make up for 

 it in girth, and planks 20 or 24 inches across, sawn out 

 of jack tree bolls, are not um'ommou. Some years back, 

 happening t'> see a number of jack fruit taken off a tree 

 while still unripe, 1 experimented with the milky juice 

 that exudes from the fruit stem. I gathered the juice, 

 and wliippiug it up like one does cream, I secured a 

 viscid mass out of it that looked uncommonly like 

 (caoutchouc) ludiarubber. Thia mass I put away in 

 the shade to dry, and in due course I found it get hard 

 and rpringy. I then gdl, several ounces of this 

 " caoutchouc," and with it moulded a cup and a vessel 

 like a milk jug. These mouldings were quite firm, but 

 at tlie same tinn' very sticky. Well, to get rid ot the 

 "stickiness," if I may so term it, I used some oil, having 

 for result a polished, smooth surface. I then placed 



the articles on the, kitchen smoke flue opening to dry 

 and brown ; unf(.rtunately I was called away suddenly, 

 iind had to absent myself for two or three days, and as 

 I had left no instructions regarding my "caoutchouc" 

 vessels, I found on mj rtum no vessels at all, l.ut a 

 mass ot viscid, dark brown, thick syiupy fluid not unlike 

 varnish. Now, from this experiment I deduce tbat the 

 jack juice contains a substance like caoutchouc — elastic, 

 leathery, water-resisting, and capable of removing pencil 

 marks. I hiid not the chemicals to test ihe qualities of 

 the substance, and to compare the same with India- 

 rubber, and, therefore, I do not feel justified in calling 

 it Indiarubbiir. 



I was careful to test the quantity I obtained, and on 

 apportioning it to the number of fruits I tapped, 

 I found that each fruit could yeld fully two ounces 

 of milk, and from it I got nearly one-and-a-half drachm 

 of rubber (I use t'lis term till another is found, or the 

 substance is proved to be other than caoutciiouc). If 

 this substance is caoutchouc, and ea*h tri'e yields only 

 20 fruit, the result would be four ounces of rubber 

 per tree.* I have not tapped the jack trees in order to 

 continue these experiments, but I have not the least 

 doubt but that they could tapped aa the rubber trees are 

 done. 



Now, if we look at the fruit of the jack, it consists 

 of a number of "flakes," each flake covering a seed. 

 This soft covering is very juicy and sweet, and if heated 

 with water and allowed to ferment, and then distilled, 

 it yields a wine of fair strength, but rather strong flavor. 

 1 see no reason why, with the aid of certain deodori- 

 zers, this strong taste and smell could not be mellowed 

 down, and a full-bodied mellow liquor, not unlike 

 some of the Marsalas, be produced. Again, the seed, 

 when roasted and ground down, is a highly nutritious 

 article of diet, very like the flour made out of the 

 Trappa by the Cashmerees. I believe it contains a very 

 large percentage of starch, and as such, could be 

 utilized in a variety of forms. Many of the common 

 jack trees yield a greater percentage of seed than those 

 that are more caruluUy cultivated, and I have seen 

 80 to 90 seeds come out of one fruit. If these seeds 

 be taken to weigh a third uf an ounce each, one fruit 

 will give us 30 ounces of flour, and twenty fruits, the 

 produce of one tree, 600ounees=37!b of flour. Now, 

 if we place the matter on a working estimate, it appears 

 as follows : — 



Say two acres of laud — R. A. P. 



Kent at one rupee per bigha ... 25 S 



Ploufjhing, cleaning, &c. .. 20 



Seedlings .. ... 2 



Planting 27 trees ... 8 



Tending do for 48 months' at 



R4 per mouth ... ... 192 



Total outlay ... 240 



Against this we have a plantation of 54 trees ; say 

 the fifth year we have eight fruits on each tree, this 

 represents an income of 8 k 27 = 216 fruits. The sixth 

 year say twice 216=432 fruits, or in two years we 

 have 648 fruits. These at two annas each for the 

 eatable part of the fruits=Pi84 with 19.440 ounces or 

 l,21.i lb of flour at I anna per tti, E70, and 1,944 

 drachms or 121 lb of rubber=@ 8 annas per lb R60, 

 or 84 >! 76 X 60=R'-20, and as the yield increases very 

 largely in a very short time, the plantation will 

 repay every expense and be self-supporting. Lastly, 



* Caoutchouc, gum elastic, or ludiarubber is a milky 

 juice found in many plants, but most abundantly in the 

 natural orders, Moracem, Artocarpucea:, Euphorbiiiciit, 

 Apiicyiiaceie, Asch'piadacnc and r<i//ni/aic(r. 'I be jack tree 

 belongs to the Artoctirpacea-, and it is a question which 

 experiment alone can decide whether rubber of sufficient 

 eoononiic value could be obtained from it. — Ed. /. A. 



