February i, 1884.] 



THE TROPICAL AGRICULTURIST. 



531 



4. Bone is an effective manure, mainly on account of 

 the phosphorus.it contains. 



5. The more thorough the pulverisation by grinding (or 

 "finer the division"; of bone, the earlier the action on 

 the growing plant. 



But the work by which this Association is more part- 

 icularly known and individualised is that abundant evidence 

 is now at hand to prove the following statements: — 



6. Undissolved phosphate in finely ground coprolite acts 

 almost identically with phosphate in crushed bone — that 

 is to say. the action is slow, but lasting, and the crop pro- 

 duced is l;falthy. 



7. Dissolved phosphate acts more quickly than undissolved 

 pho.sphate, and gives usually a rather heavier crop, but a 

 less healthy one, 



8. Too quick action, resulting in rapid early growth, tends 

 to produce ultimate disease in the plant. 



9. Steamed bone-flour possesses nearly the same rapid 

 action as the dissolved manures, combined with the healthy 

 and lasting action of the undissolved manures, and produces 

 heavier crops than either. 



Seven years ago steamed bone was unknown to farmers 

 as a manure. By boiling or steaming bone its glue is ex- 

 tracted, and grinding then brings it down, not to a coarse 

 sawdust-like state, but to a state of division like 'Wheat- 

 flour; it is reconimen led on account of its cheapness, as 

 each pound of phofiphorus in steamed bone-flour can be 

 purchased for about Gd. It is fmther stated to possess 

 the advantage of keeping the Turnip free from the "finger- 

 and-toe " disease. 



Kitrni/en on Boot Crops. — "Plants can no more grow with- 

 out nitrogen than without water or without air." 



" A full c. o,> of Turnips (say 30 tons) contains about 100 lb. 

 of nitrogen." 



" Ten to 15 lb. of niti'ogen per acre appears to be a sufficient 

 quantity to apply fur Turnips grown in granitic (siliceous 

 or clay) soils generally." 



(This applies probably to most soils that are not exposed 

 to prolonged hot .sea.sons, and that are cultivated in a 

 similar maimer to those in Aberdeenshire, i. e., receiving 

 during a short rot.ition, a fair dressing (12 tons) of farmyard 

 manure per acre, and grazed one or two years; 10 to 15 lb. 

 nitrogen would be .supphed by about jj cwt. of nitrate of 

 soda, and in many cases much less would do.) 



"Larger applications of nitrogen than 15 lb. per acre retard 

 ripening, and pioduce large watery bulbs, without much, 

 or any, increase in solid, nourishing -matter." 



" To such an e.^tcnt may this happen than 20 tons of 

 watery Turnips may not contain more nourishing matter 

 than 12 tons of imported Turnips." 



Nitmi/en on Grain Crojis. — "Nitrogen influences grain crops 

 more than jihosphorus. The reverse in the case with root 

 crops." 



"A full crop of Oats (say 8 qr.), contains about 80 lb. of 

 nitrogen." 



"It is probably unsafe to have less than 160 lb. of nitrogen 

 at the command of the grain crop." 



" The soil farmed as indicated above, and aided by the 

 nitrogen in rain, may be depended upon to provide, in 

 suitable form, by far the larger proportion of the nitrogen 

 required." 



"The manurial application may, as a rule, be linuted 

 to 2-T lb. of nitrogen. 



(This would be pro\-ided by about IJ cwt. of nitrate of 

 sida, or IJ cwt. sulphate of" ammonia, or by 2 cwt. of 

 I'eruvian guano.)— 'jacrfenna' Chronicle. 



THE TREES YIELDING BENZOIN. 



BY E. M. HOLMES, F.L.S. 



The benzoin which enters into English commerce includes 

 four varieties, named respectively ' Sumartra, Palembang, 

 Penang and Siam benzoin. These e.Nhibit certain charac- 

 teristic appearances by which they are easily recognized, 

 aud three of them, namely, Sumatra, Penang and Siam 

 benzoin, are probably derived from three distinct plants. 

 The botanical source of Sumatra benzoin was determineil 

 by Dryander, and an account and figure of the jiiant 

 were published by him in the Philosophiml Transactions, 

 for the year 1787, l.\xvii., p. 303, but the trees which yield 

 the other varieties have as yet never been identified with 

 certainty. The Penang benzoin is similar in appearance 



to the Sumatra kind, but it has an odour which is quite 

 distinct and resembles that of storax. It is in all prob- 

 ability not produced by Stt/ra.v benzoin ; but we have as 

 yet no accurate information concerning the botanical source 

 of Penang benzoin. The authors of ' Pharmacographia ' 

 point out that it may perhaps be the produce of iSti/rax 

 i-ubdenticiilata, Jliq., since tliis tree, which occurs in "West 

 Sumatra, has the same name, " Eajoe Keminjan," as S. 

 benzoin, and Miquel remarks of it an etiam bcnzoifenrm ? 

 That these two species sliould receive the same native 

 name in Sitmatra is not surprising since the leaves are 

 very similar in shape and appearance aud the fruit of 

 S. subdenticulaia apparently only differs from that of 

 & ienzoin in being obovate instead of globular and 

 depressed. 



Palembang benzoin resembles the Sumatra sort in odour 

 and differs from it chiefly in its much greater transparency 

 and in yielding, as I am informed, a larger percentage 

 of benzoic acid. It frequently contains moisture, and if 

 recently imported specimens are placed in a bottle they 

 soon become mouldy. Concerning the tree which yields 

 Siam benzoin, nothing definite has hitherto been ascert- 

 ained, although as long ago as 1859, Mr. D. Hanbury 

 wrote to Sir E. H. Schomburgb, asking him to investigate 

 the origin of the resin, and to find out whether the tree 

 which yielded it was really Stj/ra:i- lionzoin. Nor have 

 subsequent inquires been more successful. The only ac- 

 count extant of the mode of collection of Siam benzoin 

 is that given by Sir K. H. Schombmgh, who was British 

 Consul for some years at Bangkok. He, however, never 

 visited the region producing benzoin, and could therefore 

 only give information at .second-hand. He represents that 

 the baik is gashed all over, and that the resin which 

 exudes collects and hardens between it and the wood, the 

 former of which is then stripped off. The authors of 

 * Pharmacographia,' remark that it is evident that all Siam 

 benzoin is not thus obtained. Schomburgb adds that the 

 resin is much injured and broken during its conveyance 

 in small ba.skets on bullocks' heads to the na igable parts 

 of the Sleuam river, whence it is brought down to 

 Bangkok. 



The state of our knowledge of Siam benzoin being thus 

 imperfect, it occurred to me to write to Mr. R. Jamie, of 

 Singapore, to ask hira for information on the .sul>ject. 

 This gentleman takes great interest in all that relates to 

 phainiacy, and has, 1 believi', been a liberal contiibutor 

 to the Jtuseum of the North British Branch. A few 

 weeks ago I received from liim a box of specimens for 

 the Museum of the ' Pharmaceutical Soci*;ty,' containing 

 amongst other interesting and valuable donations some 

 sections of the trunk of the Siam benzoin tree, and 

 herbarium specimens of the leaves, but unfortunately neither 

 flowers nor fruit ; also specimens of the Sumatra benzoin 

 tree with leaves, flowers and fruit. In addition to these 

 specimens he has contribnted some interesting information, 

 which 1 have taken this early opportunity of laying before 

 you. "With regard to the Siam benzoin plants Mr. Jamie 

 writes: — 



"My friend. Captain Hiiks, uf I'nngkok, kindly procured 

 them after very great difficulty from bis friend living in 

 the district where the gini benzoin trees are found, and 

 he writes as follows : — 'According to your request I had 

 I fifteen gun benjamin plants brought over from Suang 

 Rabang, one of the northern Laos states tributary to the 

 King of Siam, but after a deal of shifting and removing 

 baggage on bullocks, twelve of them withered up ; how- 

 ever, 1 have succeeded in getting three of them brought 

 to Chung-mai; these I now send you. The one in the 

 flower pot seems to be thriving remakably well, but the 

 other two in bamboo joints I have my doubts about. I 

 also send you some sections of wood with the bark 

 attached, and here and there you will find the gum stick- 

 ing on the wounds aud incisions made by the natives. 

 1'he flowers, I am sorry to say, I could not get, as the 

 trees have already flowered. From reliable infoimaf ion the 

 tree is indigenous in all the northern Laos states, but 

 grows luxuriantly in Suang Rabang and all along the belt 

 of mountains in this province.' 



•' In the months of April and Jlay the leaves begin to 

 wither and fall off, aud the natives thi'n make incisions in 

 the bai k, and after a sliort linie a lot of milky substance 

 exudes and soon hardens; the gum then drii s on the 



