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THE TROPICAL AGRICULTURIST. 



[July i, 1834. 



The total yield in tlie lighter fraction and resin oils is 

 about 80 to 85 per cent ; the principal loss is due to the 

 combustible gases which are given oft" in abundance during 

 the whole of the operation, and which have not hitherto 

 ^een utilized. 



The resin oils thus obtained are not identical throught- 

 out the entire distillation. They are distributed generally 

 according to their colour, into three classes: pale oils, blue 

 oils and green oils. 



The " pale oils " are the most abundant, the quantity 

 reaching 1,100 or 1,200 kilograms in each operation. They 

 are of a brownish yellow colour and rather fluid. In 

 density they vary between 0'990 and 1'000. They are in- 

 cougelable, even at very low temperatures. They possess 

 considerable lubricating properties, but present the in- 

 convenience of resinifying rather rapidly in contact with 

 the air, which, together with their odour, has always 

 limited their employment. Railway companies and miners 

 use large quantities for lubricating machinery, after adding 

 25 to 50 per cent of colza or mineral oil. They are also 

 employed, either alone or mixed with linseed oil, in the 

 manufacture of printing ink. 



The " blue oils " consist of that portion of the products 

 which passes over immediately after the pale oil. These 

 oils are more coloured and have a very pronounced blue 

 fluorescence. Their density is about '990 to l'OOO. 



Lastly, when the operation approaches its termination, 

 the " green oils " are collected, which are of a still darker 

 shade, and possess a very strong green fluorescence. They 

 are always mixed with a very large proportion of water, 

 from which it is extremely difficult to free them. These 

 oils, like the " blue oils," are more fluid than the " pale 

 oils;" they contain, in fact, a larger proportion of alight 

 spirit, the presence of which is due to the commencement 

 of pyrogenation which the colophony undergoes in con- 

 sequence of the high temperature to which the distillatory 

 apparatus is submitted. 



The blue and the green oils are employed especially as 

 lubricants for waggons used in mines. As to the light 

 spirit the proportion of which amounts to one or two per 

 cent of the colophony distilled, its employment is very 

 limited. It possesses a very pronounced odour, is brownish 

 in colour, and has a density of about 0'950. Exposed to 

 the action of the air it resinifies rather rapidly, similarly 

 to oil of turpentine. Occasionally it is used in the place 

 of oil of turpentine, especially .in making up paint for 

 out-door use. 



The resin oils, obtained by the method indicated, are 

 usually sent into commerce in the same condition. They 

 are then frequently turbid and slightly opalescent through 

 the presence of a small quantity of water distributed 

 through the mass. In order to render them limpid, M. 

 Durou has proposed to allow them to stand some time in 

 large reservoirs arranged under glass roofing, exposed to 

 the sun. Under the influence of heat and light the oil 

 clarifies pretty rapidly, especially in summer, and at the 

 same time undergoes a slight decoloration. The same 

 result is also attained by a rectification, and for this pur- 

 pose the apparatus used in the distillation of the colo- 

 phony is employed. The operation should be conducted 

 slowly. A certain quantity of light spirit is first collected 

 and set aside, after which, the oil distils perfectly clear. 

 This distillation yields very good results ; but always oc- 

 casions a loss of 6 to 8 per cent. The rectified oil has a 

 density of "972. Several processes have been proposed for 

 removing from resin oils their odour, which in many cases 

 constitutes an obstacle to their employment. 'Washing 

 with soda, followed by agitation with sulphuric acid, is 

 the process which appears to yield the best results, but 

 this method of purification has not yet received any in- 

 dustrial application. .,,„..„ 



When a lubricant for carriages is required the " brai 

 is submitted to a rapid distillation not lasting more than 

 four hours. The oil obtained under these conditions then 

 contains a large proportion of resin, which has been car- 

 ried over mechanically ; it is viscous and thick, and is 

 known as " strong " oil. To prepare the lubricant, one 

 part of slaked lime is suspended in two parts of thin oil 

 from a slow distillation, and one part of the thick paste 

 so obtained is incorporated with four or five parts of " strong" 

 oil. The resin contained in the latter combines with the 

 lime to foim a resinate of lime. The paste is stirred well. 



and then while still liquid it is run into barrels or boxes, 

 where it acquires quickly the desired consistency. These 

 lubricants are sometimes coloured by the addition of 

 powdered pigments. — Pharmaceutical Journal. 



In New Zealand a company is proposed to be formed 

 with a capital of £10,000 for the purpose of establishing 

 the culture of silk, olive, wine, colza, castor oil, and other 

 kindred industries. — Australasian. 



Australian Gum Acckoides. — At the recent Amsterdam 

 Exhibition was shown some resin obtained from Xanthorrhau 

 hastilis, called gum accroides, a native tree of New South 

 "Wales. The gum shown was a good marketable sample, 

 worth in Sydney £24 per ton ; a few months ago it was 

 sold, in London, at auction sale of gums at more than double 

 that price. The quantity collected during 18^2 was over 

 100 tons; this quantity is very largely in excess of former 

 years. The resin is used in the manufacture of picric acid 

 by dissolving the gum (or rather we should say resin) in 

 strong nitric acid : violent frothing takes place, red vapours 

 are given off, and a dark-red solution is formed, which be- 

 comes deep yellow after boiling. This solution is evaporated 

 over the water bath, and the remaining yellow crystalline 

 mass, together with picric acid, contains small quantities 

 of oxalic and nitro-benzoic acids. It is then neutralised 

 with potash and the picrate of potassium is purified by 

 two crystallisations, and then treated with hydrochloric acid, 

 which separates the picric acid, to be again purified by two 

 crystallisations. The amount of picric acid thus formed is 

 about half the weight of the gum to be used in its manu- 

 facture. An excellent spirit varnish is made from this gum 

 by adding to about one gallon methylated spirit (cold) — 

 about 2^ lb. gum, about £ lb. common resin, and about h 

 lb. shellac — then strain through muslin cloth. This varnish 

 must be used upon dry work, and is easily applied to our 

 climate ; if found not to answer in cold or damp climates, 

 we would suggest it should be tried in a warm dry room. 

 The. gum is used for staining wood, and also in the manu- 

 facture of sealing-wax, brass lacquer, and Japan gold size. — 

 Puhlic Opinion. 



Boot Pruning. — There is a Mr. Kynaston, somewhere 

 towards Wales, in England, who has made for himself a 

 reputation, and to a certain extent become an authority, 

 upon the subject of root pruning. He managed always to 

 to get a crop of fruit, whilst his neighbours got very little 

 one year, and a fair crop the next. This went on for about 

 twenty years, and some people began to think there was 

 witchcraft or diablesie in it. However, he published what 

 he called his secret, and it turned out to be nothing else 

 but rootpruning and manuring. He holds a theory that 

 every fruit tree possesses three kinds of roots — those which 

 descend keep the tree firm in the ground and supply moist- 

 ure ; those which traverse long distances near the surface 

 arid moisture to the growth of the limbs and foliage, and 

 those which form close to the trunk or pole and help very 

 considerably in the formation of fruit. The first and the 

 last are to be encouraged— in his opinion — but the long 

 stretching wood-forming roots should be discouraged. There- 

 fore, he digs a circular trench at a distance of four to 

 eight feet from the pole or trunk — according to size — about 

 a good spit deep. Then he takes a pickaxe or mattock, 

 and breaks up the subsoil in search of the long roots, which 

 when found he cuts off. He puts manure into the trench 

 along with the earth, and is careful to manure the ground 

 beneath the branches of the tree, which has the effect of 

 greatly encouraging the production of the small fibrous 

 roots that he believes are chiefly designed for the pro- 

 duction of fruit. There is one thing in his theory which 

 will perhaps not bear too close criticism. Why not encour- 

 age the production of the fibrous roots by the application 

 of manure near the bole or trunk without destroying the 

 long roots? However, he is credited with having been very 

 successful in his practice, and the hint his worth consider- 

 ation where owners have trees that do not bear satis- 

 factorily. — Adelaide Observer. 



"ROUGH ON RATS." 

 Clears out rats, mice, roaches, flies, ants, bed-bugs, 

 beetles, insects, skunks, chipmunks, gophers. Druggists. 

 B. S. Madon & Co., Bombay, General Agents 



