Vol. XV. No. 382. 



THE AGRICULTURAL NEWS. 



409 



Matte Tea Production in Southern Brazil. 



An interesting article on the production of matte 

 tea, which is a popular beverage in the southern States 

 of South America, appears in the Journal of tlie Royal 

 Society of Arts, for August 2.5, 1916. The matte tree 

 grows to between 10 and 12 feet in height, and the 

 leaves are said to resemble those of an English pear 

 tree. The grades of matte depend upon the amount 

 of wood in the leaf This tea contains only half 

 the amount of alkaloid which ordinary tea contains, 

 and for this reason is said to ' possess two great 

 advantages over either tea or coffee: It is less 

 stimulating and very much cheaper. Matte is 

 prepared in the same way as tea, and may be 

 taken with sugar and milk. In powder it is prepared 

 by infusion, putting it into a small vessel and pouring 

 thereon a sufficient amount of boiling water. The trade 

 in matte is very considerable in South America, the 

 amount exported to the Argentine in 1913 being worth 

 £1,793,800. 



The United Empire. 



United Empire (November li)l(i), the Royal 

 Colonial Institute Journal, contains several articles 

 of immediate interest to the West Indies, particu- 

 larly one on Canada and the West Indies, by 

 Mr. Evans Lewin. This puts forward views in favour 

 of and against Canadian-West-Indian political union. 

 It calls attention to an interesting tendency for the 

 great dominions to gather extra-continental territories 

 within their administrative fold. Specific reference- 

 is made to Australia and New Zealand, which of 

 recent years have taken over the affairs of several 

 Pacific islands. Without any great stretch of imagin- 

 ation, the article says, one may look forward to the time 

 when the British Empire will consist of a numl)er of" 

 self-governing communities, a series of empires withia 

 the empire, each responsible within tlie greater system 

 for the administration of other territories, which will 

 doubtless, in course of time, become equal partners 

 within specific confederations. 



Preservation of Natural Colour in Plants. 



A method is described in Mature (November 9, 

 1916) for fixing the green colour in plants. This con- 

 sists in placing the plant for a shorter or longer period 

 in a boiling solution of copper acetate dissolved in 

 acetic acid, a combination of the copper salt with the 

 chlorophyl being formed which renders the colour 

 permanent when the specimen is exposed to the light 

 after drying or after placing in a preservative solution 

 such as alcohol. 



The article goes on to say that it is essentially 

 a method, the results from which gain by experience; 

 different plants lend themselves to the treatment with 

 different degrees of success, and require very different 

 periods of treatment; the time for which it is necessary 

 to keep the plants in the boiling solution varies from 

 one minute to fort}' minutes, according to the action of 

 the copper salt upon the plant. After treatment the 

 plants should be washed (like photographic prints) in 

 running water for about two hours und then dried 

 under light pressure. 



A stock solution is made by .saturating commercial 

 strong acetic acid with powdered copper acetate. For 

 treatment, dilute the stock solution with water in the 

 proportion of 3 or 4 parts of water to 1 of stock solution. 

 The solution is heated in a non- metallic vessel, glass 

 beakers being probably the most suitable, and wooden, 

 not metal, forceps should be used for manipulating 

 the specimens. 



At the British Natural History Museum this 

 method has been used for some time past in the prepara- 

 tion of plants for exhibition purposes and good results 

 have been obtained with cryptograms like ferns and 

 algae, as well as with flowering plants. 



The method described above may be found useful 

 in some of the schools and museums in the West Indies, 



Photographic Illustrations in Agricultural 



Science. 



In glancing through the numberless periodicals 

 which are now published in connexion with agriculture 

 and the allied sciences one is struck by the great varia- 

 tion in the quality of the half-tone illusti'ations. In 

 many cases there is much that is left to be desired, and 

 the reason for this prevalent inferiority may be found 

 to lie chiefly in the fact that agricultural subjects are 

 not easy to photograph on account of the lack of 

 contrast, the large amount of detail, the difficult 

 colouring and the difficult perspective, which are so fre- 

 quently found to prevail. 



An article which should serve a helpful purpose in 

 regard to these matters appears in the AgricidturaL 

 Journal of India (Vol. XI, Part 3) and is entitled 

 Photographic Illustrations, the author being Mr. C. M. 

 Hutchinson, B.A., Imperial Agricultural Bacteriologist 

 in India. This article, which is accompanied by 

 many comparative illustrations, is most instructive. The 

 first plate shows the advantage of using evening light 

 where it is desired to bring out detail. Another plate 

 shows the superiority of an ordinary over or thochromatic 

 plate for subjects depending for proper delineation 

 upon shadow contrast rather than colour differences. 

 Two comparative photographs of butterflies show tl;e 

 necessity for the use of orthochromatic plates for such 

 coloured objects. In this illustration, where the 

 ordinary plate is used the orange-yellow colouring of 

 the underwing of one of the butterflies fails to come 

 out; the effect is seen to be obtained however by 

 employing a Wratten M plate and yellow screen. There 

 are many other similar illustrations in this article 

 which should be read by all experiment statioa 

 workers who are brought into contact with the i^uestioa 

 of photography. 



