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[MES. SATURDAY, JANUARY 30, 1892.SCIENTIFIC NOTES.Ancient Canals.The valleys of the Fait anil tiila Hi vers in Western America are intersect. .! by a vast network of ai.cien oinals, which existed hefc.-ri- the Spaniards i utorec' the country under rmado in 1552 and are, according to the traditions of the Indians, ther*dice of a vanished population. The canals extend to a grand total ol 1,000 miles or more, and must have irrigated over 250,000 acres of land. The country is littered with the ruins of adohe dwellings, potsherds, and steel ornamen's, as well as implements of stone. The American /.’a./oete/ay .v’irj says that, modern engine- rs cannot improve on the lines of these old works or in the selection of the points at which they tap the waters of the rivers.Ocean Discolouration.The discolouration of the Arctic Ocean, the Hod Sea, and other, waters by diatoms and minute Crustacea is now well known to naturali-ts. One ot the most remarkable of sueh occurrences is reported from Port Jackson, the harbour of Svduev. Suddenly the water presented in places the colour of blood. This was found to bo due to the invasion ct rapid development of a microseopic Oft which in the course of a few davs destroyed half of the shore animals. Nearly afl the bivalves in the place which it affected 'died, the oyster-beds being seriously injured, mainly, it is' believed, owing to the molluscs having swallowed it in that uncritical fashion in whieh a gaping shell-ilsh takes in what is good, had,anil indifferent, though the sea fortunately seldom contains anything noxious to the life it nourishes. This observation mav explain the sudden disappearance of oysters from loea.itles where they formerly abounded.Polar Ice.. ^ hat, then, is the greatest thickness to which the ne thus grows, and where does it grow to its gi eatest thickness r 1 have a vivid recollection of the surprise 1, in common with some other members of our expedition, felt when we first realised the enormous thickness of the llocs blocking the not t hern end of Kobeson Channel. A floe, perhaps 15 miles across, and floating 10 or 12 feet out of water, is sufficiently imp sing; but, a certain amount of scepticism attends the calculation that there is at least eight times as much of it below. Afterwards, for many months, we saw the edges of the eastward-drifting pack that filled the whole sea ground along the shore in seven fathoms and upwards, and sometimes crush inward till its entire section was exposed, or only hidden at the base by : tiie tttmhlincr rubble of ice, or the bastions of sand it pushed before it. Such ice was not to be found in land-locked hays, into which it could not drift from the sea, nor was it confined to any one spot—on. sledges followed its edge for 300 miles along the shore of the Polar Sea. If we had read the records of previous expeditions with greater care, the stupendous character of the ice would not have been unexpected. It is by no means novel. Ten degrees west of tiie farthest point readied bv our sledges under Commander Aldrich, Sir Edward Belcher , encountered it at 106 feet thick, drifting; into and grounding on the shores of Wellington Channel. Twenty degrees further on Surgeon Fisher of tiie Hecla and Griper reports floes 90 feet thick. Another 10 degrees bring us to the roast of Prince Patrick’s Island, where Sir Leopold Nl’Clintock notes, like Aldrich, how the edge of the tremendous pack rested on the ground two miles out to sea. Lieutenant Mediam, following it west to Hanks Strait,, figured the huge “blue-domed ” floes in the Parlia-i mentary reports of 1855. It was in Banks Strait I that Sir Ldward Parry was finally stopped bv the great undulating floes, reaching 102 feet in thickness, that lie tells us he had never seen in Baffin’s Sea, or in the land-locked channels he had left , behind him, hut which filled the whole sea before i him.—t asstll s Scitnci1 for All.j Luminous Paints In all Colours.A German contemporary gives the following series of receipts for these paints, whieh may prow | useful. All the above paints can be used in toe ! manufacture of coloured papers, e.., if the varnish is altogether omitted, and the dry mixtures are ! ground to a paste-with water. ’The luminous | paints can also be used as wax colours for painting I on glass and similar objects, by adding, instead of the varnish, 10 per cent, more of Japanese wax and one-fourth the quantity of the latter of olive oil. The wax colours prepared in this way may also be used for painting upon porcelain, and are then care-1 fully burned without access of air. Paintings of this kind can also be treated witli water glass. For orange luminous paint, 46 parts varnish are mixed with 17’5 parts prepared barium sulphate. 1 part prepared Indian yellow, 1*5 parts prepared madder lake, and 38 parts luminous calcium sulphide. For yellow luminous paint, 48 parts varnish are mixed with 10 parts barium sulphate, 8 parts barium chromate, and 34 parts luminous calcium sulphide. For green luminous paint. 48 parts varnish are mixed with 10 parts prepared barium sulphate, 8 parts batium chromium oxide green, and 34 parts luminous calcium eulnhi in. A blue luminouspaint is'prepared from 42 parrs varmsn. wz parrs prepared barium sulphate, 6 4 parts ultramarine Idue, 54 parts cobalt blue, and 46 parts luminous calcium sulphide. A violet luminous paint is made from 42 parts varnish, 10 2 parts pn pared barium sulphate, 2’8 parts .ultramarine violet. 9 tarts cobalotus arsenate and 3 parts Itimim 8-' r.ueiuni sulphide. I’or gray luminous paint. a5 part- of the varnish are mixed witli 66 parts prepared calcium carbonate, 0'5 part ultramarine blue, 6 5 parts /inc. sulphide. A yellowish brown luminous paint’ is obtained from 48 parts vani-b. 10 parts precipitated barium sulphate, 8 parts auripigment. and 54 pait« 1 luminous calcium sulphide. Luminous colours for ! artists are prepared by using pure Last India j. q«y ; oil in the same quantity instead of the varnish, and | taking particular pains to grind the materials as i fine as possible. I-’or luminous oil-colour paints, j equal quantities of pure linseed oil are. u-ed in plice . of the varnish. The linseed oil must ho cold-pressed j and thickened by heat. IStars and the Spectroscope.It is well known, says sir Robert Hall in the , 1'uftnhihth/ It?ini.-, that the ordinary expression, j fixed star, is a misnomer, fur almost every star 1 which has been observed long enough is seen to he j in motion. Indeed, it is not at all likely—11:15-, it is intinitely improbable, that such an object as a really fixed star actually exists. When the place of a star has been Accurately determine! i»y measurements made with the meridian circle, and when, after the lapse of a number of years, tin* place 1 of the same star is again determined I15-observation, it not utifroquontly happens that tiie two piaeesdisagree. The explanation is, of course, that the star has moved in tiie interval. Thus the constellations are becoming gradually transformed ly the movements of the several stars whieli form them. It is j true that the movements are so slow that even iti thousands of years the changes do not amount to much when regarded as a disturbance of the configuration. Tiius, to take an example, we know the movements of the stars forming tlm Great Bear sufficiently well to be able to sketch the position of the stars as they were 10,000 years ago, or as they will be in 10,000 years to come, anil though, no doubt, some distortion is shewn in each of these pictures from the present lineaments of the Great Bear, yet the identity of the group is in each case well preserved. It is, however, obvious that, if a star should happen to be darting directly towards the observer or directly from him, the telescopic method of determining its movement becomes wholly inapplicable. N'o change in its position could be noticed. It is just iiere that the spectroscope comes in to fill the vacant place in the armoury of the astronomer. It tells exactly what the older methods were unable to tell, and it does so with a certainty and a facility that suggest vast possibilities for the spectroscopic process in the future. The principle of the method is a beautiful illustration of the extent to which the different branches of physical science are interwoven. But the principle has been a familiar one to astronomers for many years. It is the facility and success attending its recent application that has now aroused so much interest. The logic of the new method is simple enough. Our eyes are so constituted that when a certain number of ethereal vibrations per second are received by the nerves of the retina the brain interprets the effect to mean that a ray- of, let us say, red light, has entered the eye. A certain larger number of vibrations per second is similarly understood by the brain to imply the presence of blue light on the retina. Each particular hue of the spectrum—the red, orange, yellow, green, blue, imligo, violet—is associated with a corresponding number of vibra-j tinns per second. It will thus he seen that the interpretation we put on any ray of light depends solely,as far as its line is concerned, 011 the number of vibrations per second produced ou the retina. Increase that number of vibrations in any way,then the hue shifts towards one nearer the blue end of the spectrum : decrease the number of vibrations per second,and the hue shifts along the spectrum in the opposite direction. From these considerations it is apparent that the hue of a ligtit as interpreted by tho eye will undergo modification if the source from which the light radiates is moving towards us or moving from us. That if the earth and the stars are approaching eacli other, more waves of light per second will he received on the retina than if their positions are relatively stationary.Climatic Cycles.The theory of climatic cycles, which possesses so irresistible an attraction for certain meteorologists, receives some support from a study just made of the prevailing winds at Greenwich. Ou the whole, since tlie year 1865, easterly' winds have‘been increasing i’n prevalence. For that year the five years’ average is 83’8, and this grows to 111*4 in 1886, that is, abiut a third of all thus recorded. On the other hand westerly winds have diminished sines* 1861; tiie five years’ average fur that year is 210-8, which diminished to 159 0 in 1887. Judging from the past we ought now to he near a decided turn of the curves, possibly past if. in the case of easterly winds. If this is correct, we ought to be prepared for more westerly and fewer easterly winds in the near future.
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London Mid Surrey Times and General Advertiser
London, Middlesex, GB
Sat, Jan 30, 1892
Page 7
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CA, USA 19 Nov 2024
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