158 



SCIENTIFIC NEV\^S. 



[Feb. 17, I £ 



These big pods are about 3I inches long, and 2 inches 

 thicli. From a single flower as many as half a dozen of 

 ripe carpels may be produced, and these may contain 

 from five to fifteen nuts or seeds. These seeds weigh 

 from So to 400 grains ; that is, from about eighteen to 

 ninetj'' seeds to the pound weight. Women gather the 

 seeds with great care. They are removed from the 

 husk and skinned, and considerable attention is necessary 

 to keep them in a fresh state. IVIr. Christy very kindly 

 sent us specimens of the fresh nut, the dry nut, the 

 paste, kolatina, and kola-chocolate ; and he particularly 

 mentioned that the fresh nuts should at once be put into 

 brine for preservation. When the women thoroughly 

 clear them, the sound seeds are carefully placed in large 

 baskets made of bark and lined with large " bal " leaves. 

 In these baskets the kola seeds are carried great dis- 

 tances inland, but they require repacking every thirty 

 days. Each package contains about 3 cwt. of seeds. In 

 this condition the kola is transported into Gambia and 

 Goree, where the principal dealings in the seeds are 

 carried on. The Gambia merchants dry them in the 

 sun and reduce them to powder, which is used, mixed 

 with milk and honey, by the tribes of the interior to 

 make a very agreeable, stimulating, and nourishing 

 beverage. As the kola makes its way inland its value 

 increases, and some of the tribes furthest removed from 

 the sea pay for the dry powder with an equal weight of 

 gold dust. 



Kola plays an important part in the social life of many 

 of the African tribes. An interchange of white kola 

 between two chiefs is indicative of friendship, whilst the 

 sending of red kola is an act of defiance. An offer of 

 marriage is accompanied by a present of white kola for 

 the young lady's mother, the return of white kola means 

 acceptance, whilst red means rejection. The absence of 

 kola from the marriage presents would endanger the 

 whole arrangement. All the oaths are administered in 

 the presence of kola seeds ; the negro stretches out his 

 hand over them whilst he swears, and eats them after- 

 wards. Care has to be taken in distinguishing the 

 female from the male kola trees for purposes of medicinal 

 use, as the false kola is bitter and useless. 



A comparison between the composition of kola, tea, 

 coffee, and cocoa shows that the proportion of caffeine 

 is higher in kola than in any of the others, and it has 

 more theobromine than cocoa. The average quantity of 

 caffeine in kola is about 2| per cent. Now this alkaloid 

 (having thirty per cent, of nitrogen) has the remarkable 

 property of diminishing the waste of the animal frame. 

 The introduction into the stomach of three grains of 

 caffeine, or the contents of one small nut, has the wonder- 

 ful effect of sensibly reducing the decay of the system. 

 Consequently the necessity for food to repair it will be 

 lessened in equal proportion. This caffeine in the kola 

 is very active, exercising an exhi arating and soothing, 

 hunger-stopping, and waste-dimmishing effect upon the 

 human frame. 



The results of the experiments which are now being 

 made in the Government laboratories, in hospitals, and 

 chocolate establishments at home and abroad, are 

 anxiously looked forward to. But enough has already 

 been discovered to show that the kola-nut must yet be 

 an important article of commerce, a fruitful produce for 

 our Colonies ; and the sooner our planters cultivate it to 

 meet the growing demand, the better it will be for them; 

 otherwise they may be again outstripped by the dashing 

 enterprise of our Continental rivals. 



JAPANESE MAGIC MIRRORS. 



'T'HESE interesting examples of Japanese work are 

 circular metallic hand-mirrors, having figures in 

 relief on the back. The reflecting surface is highly 

 polished, and reflects the face as well, apparently, as 

 mirrors of silvered glass; but when it is used to reflect 

 the direct rays of a powerful light upon a screen, the 

 reflection shows, with a moderate degree of distinctness, 

 the figures that are at the back of the mirror. This 

 phenomenon is popularly ascribed to the marvellous 

 ingenuity exercised by the Japanese metal-workers in 

 the production of the mirrors, but from a paper contri- 

 buted to the Franklin Institute by Mr. F. E. Ives it is 

 capable of a very simple and satisfactory explanation. 

 The mirror experimented on is described as being thin, 

 made of very elastic metal, with the polished face 

 slightly convex, and with the general form of the back 

 slightly convex, measured from the top of the ornamental 

 relief figures and rim. Mr. Ive's idea is that the mirror 

 is simply cast (not stamped, chiselled, or hammered), 

 and that the apparently magical reflections are pro- 

 duced merely in the ordinary process of grinding and 

 polishing. For if, in the operation of grinding the face 

 of the mirror, it be held against the grinding surface by 

 a flat support at the back, the pressure would flatten it 

 until the ornamental relief figures rested upon the support, 

 and on those parts the mirror would offer a positive 

 resistance and be ground away rapidly ; but the thin 

 parts between the relief figures, having no direct support,, 

 would be sprung back by the grinding pressure, and 

 would therefore be ground away less rapidly. On 

 removal of pressure the back of the mirror would regain 

 its original form, but the face, ground away irregularly,, 

 and most where the relief at the back was greatest, 

 would have a slight but irregular convexity, greatest on 

 the thin parts between the relief figures. Mr. Ives 

 attributes the pattern produced in the reflection 

 to this irregular convexity, and tested the truth 

 of his explanation by adopting means to render 

 the mirror face perfectly flat, when, of course, if his 

 theory were correct, the pattern would vanish from the 

 reflection. This flattening was accomplished by super- 

 imposing on the mirror a heavy piece of plate glass,, 

 with the result anticipated. The figures vanished from 

 the reflection, and the credit given to Japanese mirror- 

 makers for mystical workmanship seems to have been 

 undeserved. 



Walker's Portable Miner's Electric Lamp. — This lamp, 

 is at present made in two forms. In one, which is round, are 

 two cells of a bichromate-carbon-zinc battery ; in the other, an 

 oval one, there are three. The cells are made in a particular 

 form, the carbon itself being the containing vessel. On one 

 side is a strong lens faced by a parabolic reflector, the two- 

 being held by a strong brass cylinder attached to the outer 

 case, which is also of brass or copper. The cells contain the 

 usual porous cells and zincs, and are closed by an india- 

 rubber pad, above which the connections are made in a simple 

 and efficient manner. A second pad of indiarubber is placed 

 above this, and is retained in its place by the cover, which is 

 held by screws, or a lock, as desired. A stout handle sur- 

 mounts the whole. The smaller lamp, made of a cylindrical 

 form, weighs 5 lbs., and gives a light sufficient to read 

 ordinary newspaper print at 6 feet from the lamp for ten 

 hours. The cost of renewing the chemicals used, the incan- 

 descent lampj and incidental repairs, is stated to be not more 

 than |d. per day for the small lamp, and id. per day for the 

 large one. — Electrical Review. 



