Science

Wairarapa Standard, Volume XX, Issue 2053, 8 April 1887, Page 2 (Supplement)

Science

Curious Facts About Meteors.

Meteors are not incandescent when they reach the ground, but are still too hot to handle. Sometimes the high temperature is limited to their surface, while within they are extraordinarily cold. The spectators of a meteoric fall at Dhurmsalla, India, on the 141b of July, 18*10, eagerly broke up the stones, still burning hot on the outside, and were greatly surprised to find that it was impossible to handle the inside parts on account of the extreme coldness. A similar observation was made on the 10th of May, 1883, at Alilanello, near Brescia. The contrast between the central part, still retaining the intense cold of the planetarv spaces, and the outside, which only a few minutes before had been red-hot, may be easily understood when we reflect on the feebleness of the conducting powers of stony sub-lances, and the very short time that they bad bees heated. One effect of this heat persists. and is obvious at first sight as a general characteristic of meteorites, in the shape of a black crust, entirely covering them. It is imt a millimetre thick, and is generally dead, but forms in some especially fusible typ s a glossy enamel. The some effect, of vitrification, is produced by lightning on rocks which are struck by it. The incandescence of which this is the effect, and which had been observed in the meteor flying in Uie distance, is the result of the extreme .speed with which the body penetrates the atmosphere.

It is. unfortunately, very rarely possible to find the fragments projected by meteors ; and it is only under quite exceptional circumstance?, even in populous countries, that ore is discovered among the clods and under the vegetation by which they are commonly concealed. The observer enjoys the illusion of supposing he sees them fp.U at no ■great distance from him ; but he will hardly ever file! one if be looks for it. Probably three quarters of them are swallowed up by the sea.

'Vo do not know in what regions of space meteors originate, nor what courses they follow before they come within the sphere of the earth’* attraction. They hj .vc been suppose) to he cj -ctions from volcanoes in the no ion. If this were the case, they would have to he Mipp-.sr.d 1,, true heen ejected by the eruption with velocity enough to pass the neutral point, or the point whore a body i.- cijnaily attracted hy the moon and the earth. That velocity should be at least two thousand, two hundred and severity metres a seeoul. or about live times that of a cannon hall : it it wore less, the mas- would fall back to the moon.

Another more probable supposition is that they come from a gmnp of minute asteroids which revolve in tiic space bo I went liars and Jupiter, whose orbits cross those of the large planets, ours included, and are occasionally mot by the earth in its course. There is nothing else, since the beautiful researches of Schiaparelli have connected the netiodieal swarms of shooting stars with comets, to assure us that they do nut come from still more distant parts of the sky, or even from without the solar system. About twenty-two elements, all known to (lie chemistry of the earth, have been recognized ns present in meteors. Among these, ir. .11, silicon, magnesium, nickel, sulphur, phosphorus and carbon, arc the most important. While they are all clad externally in a common livery, meteorites, when examined in their fractured parts, along with traits of similarity, present considerable differences. They have been classified, according to their tvpcs, into four groups, according to the proportion of iron they contained. Those of the first group are composed almost wholly of iron, which is known as meteoric iron. It is always alloyed with nickel and a few other metals, and contains carbon free or in Combination, ns in steel, with frequently sulphuret and phosphnret of iron in scattered globules and grains. It is always recognizable by a single peculiarity in its structure. If wo moisten a polished surface of it with an acid, we shall immediately observe the appearance of numerous straight lines, as fine and as true in their parallelism as if made with an engraver’s tool, and crossing one another in a network of regular geometrical figures. These designs, called the figures of Widmanstaettin, after the first observer of them, result from the fact that the metal is not of homogeneous constitution. It is composed of two alloys of iron and nickel, in a crystalline condition, one of which, not living affected by the acid, stands out in relief from the other which is attacked by it.

The Dreams of the Blind. A paper read before the biographical section of the American Association for the Advancement of Science w'as on " The Dreams of the Blind,” by Dr. Joseph Jastrow. The object of the paper was to determine the extreme age at which a child may become blind and yet lose all memory of the visible world, so that it no longer sees in its dreams. Almost all dreams of normal persons are sight dreams, and a dream is often spoken of as a vision. The blind are deprived of this most important sense; but if they have not been born blind, they may remember enough of what they have seen to enable them to imagine how things look, and when the imagination has free play in sleep, to picture themselves as in full possession of all their senses. Physiologists would explain this by saying that during the years in which they saw, a certain part of the brain has become educated to receive and interpret all these messages which the eye sends, and that when this part of the brain acts spontaneously in sleep, the person dreams of seeing. Such a portion of the brain would be called the sight centre.

If now wc find out the latest age at which blindness may set in and yet the person keep on dreaming of seeing, we shall lind out the time it takes for Ibis, sight centre to develop. For this purpose about 200 blind persons of both sexes were questioned at the institutions for the blind in Philadelphia and Baltimore, and it was found that those who became blind bvlute their titili year never dreamed of seeing ; of those whose sight was lost between thcjil’lh aval seventh year,some did and some did nut see in their dreams ; while all whose eyesight was destroyed after the seventh year had quite as vivid dream visions as seeing people. The fifth to the seventh year is thus shown to be the critical period. This period corresponds with the age which authorities assign as the limit at which a child becoming deaf will also become dumb, and also with the age of one’s earliest continuous memory of one’s self.

it Is interesting to note that blind persons dream quite as frequently as normal people, and that with those who do not see in their dreams, bearing plays the principal part. When dreaming of homo, for instance, they will hear their father’s voice or their sister singing, and perhaps will feel the familiar objects in the room, and thus know they are at home.

Paper.—Not only will paper eventually take the place of wood, but also of a good many metals and of stoneware. A portable paper bath tub is one of the latest ideas, and pots, plates, knives, forks, stoves and engines made of paper have a largo and inereasing market. A large part of the beautiful bronze ornaments and statues seen in public plac s and offered fur sale iu stores devoted to (lie sale-if ancient and modern bronzes are made of a composition the principal clement, of which is paper or fibre. A, man today can wear paper shoes and clothes, eat from paper dishes with paper knives and [oiks, s'-rved- upon a paper table, sit on a pap-T chair, sleep in a paper bed, in a i", a, i- irpijUd with paper, wash in a paper tub r bow l, live in a paper house, ride in a p:ii„o . in . r i mriage. sail in a paper boat, build up a fortune on paper, and yet the industry is only iu its infancy.