SCIENCE NOTES.

Otago Witness, Issue 2302, 14 April 1898, Page 48

SCIENCE NOTES.

— A new process has been suggested that will effectively protect iron from rust. A solution of ferrocyanide is mixed .with a flaxseed varnish, to which has been added a little turpentine or benzol. The evaporation Df the alcohol leaves the flax3eed varnish, fcrhich forms a coat and protects the cyanide Df iron, which is deposited upon the mefcal by the use of the ferrocyamde. The only preparation iron requires for this treatment \s to remove any rust that may have formed m it, which may not admit of the action of the solution. — Professor Crampton, of Columbia Uniyersity, is said to have discovered a remarkable process of grafting insects in the ambryonic state. He take 3 the pupas of different species of insects, partially freezes them to prevent the flow of blood, then decapitates them and grafts their heads on other bodies with paraffin wax. The parts Invariably grow together. Professor Orampton bas thus produced an amazing collection Df insect monstrosities, including two-headed butterflies, moths without tails, some v/ith two abdomens, others with two breasts and jno backs, and, in fact, all imaginable varieties. — A substitute for German silver can be made by the use of manganese, the different metals and their proportions being as follows :— Copper,- 67*25 per cent. ; manganese, 18-50 per cent. ; zinc, 13-00 per cent. ; aluinSnum, 125 per cent. The colour of this jnetal is said to be very good, resembling German silver closely. ' It isr fully as strong jas the best German silver, and has superior casting qualities, which will be- appreciated, by foundrymen who have experienced Boms of the difficulties in casting German eilver: „-■■—-—- — M. Martel, the well-known French cave . iiunter, has -explored an " aven," or natural - pit, in the limestone of the Lozeve, France, with remarkable results. Ait«* 4©BCBadjpg

a vertical shaft for about 2,00 ft be found an immense hall, sloping downwards, and at r the lower end a " virgin forest " of stalagmites, resembling piae and palm trees. | Many of them are very beautiful, and one, ; over 90£fc in height, reaches nearly to the ; vault of the cavern. Nothing like this forest ; of stone has been observed in any other j known cave or pit. j — While aluminum is known to be easily attacked by alkalies, even strong acids do not injure it in the least. It behaves, almost as indifferently as platinum. Aluminum may be-left 'to the strongest nitric acid for days without any tffect being visible. This pro--.peity .makes, aluminum very ..valuable for •certain purposes. The writer uses aluminum hooks to'take' out photographic s plates from tbe acid trays.. No other material is capable of- withstanding the action of the rather strong ' nitric acid ns.ed for acidifying the plates for' aay length of time; even bard rubber hooks-were corroded in a comparatively short .time. The aluminum hooks were found to be invaluable and have the advantage of infracgibility over glass hooks. For acid funnels aluminum may also be employed to advantage. — Technische Mittheilucgen. THE SUN. BIS CONOENTHIC SHELLS. Every schoolboy knows that he is not qnite so clever as he is supposed to be since the days of Macaulay, bufc a good many schoolboys are aware that the sua is a blue star 860,000 miles in diameter and hotter than the hottest furnace. Apparently he is made up of several concentric shells like an onion. ■ Hie liquid kernel is probably as dense as pitch. It is surrounded by the " photosphere," a jacket of incandescent clouds or vapours of iron, manganese, and other heavy elements which have a granular or flocculent aspect in the telescope. This luminous veil is what we ordinarily see, and if we even catch a glimpse of his fiery heart it is only through the " sunspots," which are probably immense gaps in the clouds made by outbursts of heated gas. Above the photosphere comes a layer of cooler vaponrs and light gases — namely, hydrogen and helium. This is the chromosphere, and stupendous jets of blazing -hydrogen are seen to burst through the photosphare into it. These are the famous " red flames " or " prominences," which hem the black disc of ' the moon during a total eclipse with a fringe of rosy fire. Some of these flames rush to a height of near 100,000 miles in 15 or 20 minutes. Higher still is the " corona," an aureole of silvery light not unlike the nimbus of a saint, and streaming for hundreds of thousands, perhaps millions, of miles beyond the solar sphere. It seems to consist of meteoric stones illuminated by the sunlight and the glowing vapours of " coroaium," a very light element unknown on the eartb, and perhaps also of electrical discharges. Were it. not tbat our atmosphere absorbs the blue rays of light better than tbe ted, the corona, like the orb of the sun, would probably appear 1e33 white. — Daily News. INSECTS AND FLOWEES. EXPERIMENTS TO SO WE AN INTERESTING AND IMPORTANT QUESTION. For some time past naturalists have been exercising themselves over the question o£ what really constitutes the attracting element of flowers visited by insects. The result has been that numerous experiments have been performed with the view of settling this point. Professor Plateau, o£ Belgium, has devoted considerable time and attention to such experiments, and bis conclusions are distinctly interesting. In the " Ball, de I'Acad. des Sciences de Belgique " he sums up tbe results of his investigations :— In seeking for* pollen or nectar, he says, insects are guided only to a subsidiary extent, by the sense of sight. They continue to visit scented flowers after the coloured parts have been almost entirely removed. When flowers of the same species vary in colour, they exhibit neither preference nor antipathy for one colour over another. Inconspicuous flov/ers hidden among foliage attract large numbers of insects. Artificial flowers made of paper or calico, even when brightly coloured and closely resembling real flowers* %re not visited bx insects, ba6 jtbey

are when made of green leaves which have a vegetable scent.

If flowers which have little or no nectar, and which are therefore habitually neglected by insects, are smeared with honey, insects are attracted in large numbers. On the other hand, i£ the nectary is removed from flowers habitually visited, their visits cease at once. The author bas paid especial attention to entomophilus flowers, and finds that their exemption from the visit 3of insects is due mainly to thsir not being provided with honey. From all these facts M. Plateau draws the conclusion that the guiding sense to insects in visiting flowers must; be chiefly the sense of smell.