SCIENCE NOTES.

Dominion, Volume 1, Issue 275, 13 August 1908, Page 8

SCIENCE NOTES.

NOVEL THEORY OF THE EARTH'S ORIGIN. THE "PLANETESIMAL HYPOTHESIS." Before tho eighteenth century closed and quite universally throughout the nineteenth, the earth was believed by geologists to have onco been a highly heated nglnilous or gaseous mass and to liavo passed through stages of refrigeration to its present state. This conception is tho one formulated in accordance with tho well-known "nebular hypothesis," and it marks the connection of geology with astronomy and celestial mechanics. Grave doubts liavo arisen in tho minds of ,somo, however, as to its truth, and despite tho significant astronomical evidenco and analogies, tho endeavour has recently been mado by Professor T. C. Chamberlin to formulate an alternative conception which would, perhaps, involve fowcr difficulties.

Instead of a highly heated, and subsequently cooled and solidified, gaseous original, minute particles of matter, which may hnvo been molecules, aro believed to liavo moved in orbits around a common ccntro in a manner similar to tho solar system of today. In their evolution they became aggregated into larger bodies such as tho planets and the earth, continuing in groups tho motions and relations which they possessed when individuals.

As tho mass gradually increased, tho pressuro of tho outer layers consolidated the core, and by tho mcchanical changes involved produced thoso internal stores of heat with which wo aro familiar in volcanoes and in deep borings and mines. Vapours or liquids in tho original cold particles are believed to liavo been gradually squeezed out by this pressure. Tho little particles are called planctesimals or diminutive planets, and tho hypothesis is styled the " Plauotesimnl Hypothesis." It is perhaps too soon to forecast the influence of this new conception upon geplogic thought. Like all attempts 'to formulate primeval conditions, its data are partly matters of observation, partly assumptions. Speculation enters in a very large degree, and, as in tho case of various and widely differing estimates of the age of the earth based on assumed rates of cooling, once tho data woro provided, mathematical reasoning goes to a conclusion with unerring accuracy. But tho correctness of the solution turns on tho reliability of the original data, and where these aro.so largely assumptive tho conclusions aro from timo to time subjcct.to change. The field geologist, whoso solutions of smaller problems turn upon carefully observed data, inevitably considers all tho formulations of views regarding remoto times and conditions ossentially as working hypotheses, much less firmly established than many other results, and to bo taken much less seriously. Yet wo must liavo a starting point, and tho striking contrasts of 1 the older and tho later viows cannot but impress everyone who reflects upon them. The former postulates a highly heated original; tho latter a cold one. Tho one begins with gaseous matter; tho other with solid. Tho ono draws upon an original but diminishing storo of heat; tho other develops heat continuously by mechanical processes. In many way the two aro diametrically opposed; yet some liavo raised the question, whether, in order to obtain a swarm of separate cold particles, we must not in our thought go still farther back to a gaseous or nebulous source, and it is not clear that wo liavo j;et escaped the necossity of at least the essential feature of the nebular hypothesis.—"Scionce Sittings."

WHY A CAT FALLS ON ITS FEET. A Frenchman, of an ingenious turn of mind, has constructed an experimental model in order to show why a cat always falls on its feet. Ho camo to know that it is ono of tho laws of mechanics that a body or system of forces cannot sot itself in rotation as a whole. If ono part of it begins to rotato another part must rotato in a reverse direction as a compensatory force. A simple examploof this is furnislied by tho experiment of twirling an oar in tho rowlock of a boat (without allowing tho oar to touch tho water) ;• tho boat will begin .to rotato in a direction opposito to that of tho rotatory oar. Now at first sight it might appear that tho cat defied this law of mechanics, sinco in falling it seems always to rotato its body so that its foot como undermost... ' But tho Frenchman, M. Hartmann, shows reason for supposing that a cat is really an example of compensatory rotation. Ho has mado a model of a primitive cat out of cardboard. Tho' cat is a cardboard cylinder with four drumsticks, or rods, stuck-in it for legs. On tho inner side of tho cylinder,- furthest from the forelegs, ho has a species of tail, also of cardboard, which is mounted on a strong moveable iron wire. This iron wiro is the termination of the axis of a spring concealed in tho body of tho cat. This spring can only bo released and allowed to como into play when ono looses a string which comcs out of tho cardboard cat's stomach. M. Hartmann hangs his cat by this string so that its four feet point upwards. When tho. string is cut the cardboard cat will fall, but at tho samo time the spring will bo released, and as it comes into play tho iron wiro and tho tail attached to it will begin to rotato with considerable speed. If tho height of tho fall is sufficient, and tho dimensions of tho apparatus and tho strength of tho spring are appropriate, tho cardboard cat as it rotates will always fall on its foot. Thus, evidently, the reason a cat always falls on its feet is that it rotates'its tail with sufficient vigour to produco tho desired mechanical results. On this hypothesis a eat without a tail if dropped from a convenient height should be unable to regulate its fall.—"Ninth Life," in "Tho Scotsman."

A SLEEP OP 87 DAYS. A lady named Mrs. Beulah Hawkins, who has been asleep in a hospital for eighty-seven days, awoke tho other day. When asked, if. she remembered anything previous, to her sickness Mrs. Hawkins replied that she recalled many times when she was asleep many tilings that had happened in her life before, and oven took pleasure in such reminiscences. "When I awoke,", she said, "I was frightened. When I- collected myself I cxrald remember a number of things. I could remember vaguoly tho remarks made by doctors and could see, or remember seeing, a number of men passing mo. I am told that this occurred when a number of medical men -saw me to-night, only a short time before I awoko. I never felt hungry or cold during the time I was in tho trance. Positions did not tire me and I felt as if in a nightmare a great deal of tho time. I had no control over my mind or power of specch when I was conscious, and although I tried a number of times I was unable to make a sound. Part of 'mo seemed paralysed and my mind was beyond my control. I feel very much awake now; in fact, I am afraid oven now to sleep again."

[S HORSE FLESH ANY GOOD TO EATP

People in this country evince disgust at tho mero mention of tho suggestion that a horso steak can rival tho usual beefsteak as regards flavour and tenderjiess. But thero are connoisseurs who allege that a Chateaubriand steak is all tho better when it is prepared from the flesh of tho horse. Thero is somo idea that hard work renders tho fleshy parts of tho animal unfit for food, and yet in countries where it has' been the custom to cat horseflesh tho demand is rapidly growing. In Paris, for example, it is just reported that last year close upon 50,000 horses were - killed for food. It would appear, however, that tho consumers are to be found chiefly amongst tho poor people. Still, tho fact remains, as pointed out by tho "Lancet, "that horseflesh is a nutritious meat and it can be prepared in such a way as to bo an attractivo moat food which need not bo tough or objectionable from tho point of viow of flavour. Thero aro no health reasons against tho uso of it, and, indeed, tho immunity which tho horse (unlike tho ox) enjoys from consumption is a decided point in favour of tho uso of horcsflosh as against beef.