SCIENCE NOTES.

Dominion, Volume 1, Issue 269, 6 August 1908, Page 8

SCIENCE NOTES.

MACHINES MADE QY MAN. MARVELLOUS SCIENTIFIC INSTRUMENTS. Dr. Carl Snyder has just demonstrated that the sensitiveness of all human organs seems very gross indeed,' as compared with that of the implements of a present day laboratory. Wo think of tho eye arid the ear as marvels of mechanism. However, a photographic plate, coupled with a telescope, will discover millions of stars whose light tho retina does not appreciate; and the microscope, with its revelations of the world of tho infinitely small, evidences tho comparative crudeness of tho' human senso of sight. The car hears but little of what is going on about us. Tho microphone makes the tread of the fly sound like a tramp of cavalry.

Our heat-sense is very vague; we cannot realise a difference of temperature beyond one-fifth of a degree. The Darometer, howover, an instrument 200,000 times as sensitive as tho skin, will noto a difference of a millionth of a degree. A galvanometer will flex its finger at the current generated by simply deforming a drop of mercury so as to press it out of a spherical shape into that of an egg. The amount of work dono by a. wink of tho eye would equal 100 billions of the wiaka marked on tho scale of a very delicate instrument; even this performance, however, is far surpassed by the "coherers" of Branly, Qf Paris, by which tho Hertz waves of wireless telegraphy are caught in their pulsings through space, the range of impressions which we get from lifting an object is very small; an ordinary chemist's balance is somo. 20 million times as sensitive. The latter will weigh down the 200 th part of a milligram. . Without such instruments as theso wo should know very little of tho world about us. With them we have como to know a great deal. They make it evident that our senso. gives us reports only of a comparatively small number of comparatively gross stimuli. ...

QUESTIONS THAT BAFFLE SCIENCE. " Why is it that modern science., which has wrought such wonders, is unable to clear up soma of the commonest phenomena, such, for instance, as the attraction' of gravitation ? " says the "Literary Digest." "Science has beoa severely criticised for this inability. She has even been callod hard names;'it has beaa said that she is 'bankrupt'—unable to keep her, pledges. In an articlo on 'The Scientific Development of Knowledge,' contributed to the ' Kevuo Scientifique' (Paris, FobruaTy 1), Gustavo Le Bon draws a distinction between the power of science to ascertain facts and to explain them. ' Unfortunately scieuco has done scorcely more tho'i to sketch out roughly tho. explanations of things. Her slow methods do not permit hor to improvise solution's for all questions. Far from clearing up the numberless mysterie-. around lis, she has often made them oniy deeper.' The result, in many minds, has been a defianco that has often led them to Speak of tho 'bankruptcy' of the learned. This excessive mistrust, succeeding a not lesd excessive confidence, is very natural to badly equipped minds. Science has, in fact, a somowhat disconcerting double charactershe solves formidable problems, and is poworloss before apparently simple ones. She discovers steam-power arid electricity', and bends the forces of nature to our needs. Nevertheless, she cannot yet' tell ■ why ■ ' the acorn becomes an oak,, why a-stone, falls toi the ground, why a stick of sealing-wax,.when rubbed, attracts light bodies. Sho.is'full of ' whys that remain .unanswered.' "

MASTICATION. There is a prevalent idea that slow eating is very favourabk to digestion, but this, says a famous physician, is largely fallacious/ Tho important point is not that we eat slowly or fast, but that when wo do eat wo chew with "energy. Of course, where the haste is due to some, mental anxioty, this may injuriously prevent the flow of tho digestive juices. Slow eating begets a habit of simply rnumbling'thb food without roally masticating it, while the hurried eater is inclined to swallow his food .before proper mastication. Henco, hurried eating is bad, but rapid mastication is advantageous. It concentrates our energies on the act in question, and lience more thoroughly accomplishes it. Moreover, energetic chewing stimulates the secretion of saliva, which is ,of great importance to- digestion in the most favourable manner.

CONCRETE SHIPS. . Italy, according to present indications, will soon give us seagomg_ steamships with hulls made of concrete. The first occasion on which concrete with used as a shipbuilding material was ,in 1855, when a small .boat made of it was exhibited at tho Paris Exhibition by a Frenchman named Lambot. This vessel which is still afloat, was constructed of wire netting covered with cement. It was not until 1896 that tho matter was taken .up again, and then an Italian named Gabellini constructed several concrete vessels of about 120 tons, some of which aro still in use on tho Italian rivers... Somo years later tho Italian Government gavo instructions for an experimental boat to be built of concrete. This boat, of 120 tons, was built by Gabellini, and was subjected to severe tests in tho dockyard at Spezia. A much larger iron vessel with a sharp ram was directed against it, but no impression was produced on or damage done to the concrete ship.' The result was that several similar vessels wore built for tho Italian Government. • The general method of construction is as follows: —Tho frames and longitudinal beams are made of concrete reinforced with round bars of iron, and tho skin consists of a' single or double layer of concreto stiffened with wire netting, and made perfectly smooth and watertight by an external coat of purece-' ment. Tho boats cost almost nothing for maintenance, aro fireproof, and cost about half as much as iron vessels of tho samo capacity. An Italian engineer, Signor d'Adda, has also submitted proposals to the Italian Government for the use of concreto armour on warships, and a series. of ■ trials to test the resisting powor of reinforced, concrete is to be mado. . ' ' '

INSENSIBILITY BY ELECTRICITY. : Doubt is now cast .on the value of insensibility for surgical • operations produced by means of electricity, the 1 discoverey of which - was recently recorded. Dr. R. Mansell-Jones thinks that olectrical currents capable of producing anaesthesia (insensibility) in the human being would seriously injure, the brain. Some cats and dogs appear readily to succumb to the influence or electric currents, but, our authority argues that as those animals are also easily hypnotised by various means, lie could never be certain whether their anaesthetic condition was not due to hypnosis; at any rate, from experiments carried out on himself and friends, the human brain does not appear to bo susceptible like an animal's, and this may probably be due to it being more highly organised. He has, however, found that the application of sinusoidal currents, and also rapid electric vibrations to the crown of the head and forehead,' aro often oxtremoly useful as an aid in . the production of the hypnotic state in thoso patients who do not easily succumb to the ordinary methods; but this is probably duo to the patients being of tho opinion that they numb the brain, as tlioy aro much too weak to havo any great anaesthetic action. Hypnotic suggestion, continues Dr. M'ansell-Jones, is undoubtedly an invaluablo aid in the treatment of all kinds of diseases and functional derangements, and especially is this tho case when it is judiciously combined with internal and external romedies. "It is difficult to account for tho marvellous results," ■ he adds, "which . aro frequently obtained by the judicious and careful employment of hypnotic suggestion: it may bo duo. to tho temporary suspension of the control of tho objective consciousness "permitting tho subliminal consciousness, which governs the bodily functions, to bo uioro amenablo to tho suggestions which aro made; however, whatever tho true explanation may bo, it is high time, in our own interests, that those results should bo universally reoognised by the members of ottrproi.jEesaion.=nSoionoa Sift/in®*"-