Scientific.

New Zealand Mail, Issue 245, 20 May 1876, Page 5

Scientific.

Pi’ofessor Balestrieri, of Naples, has invented an apparatus to which he gives the formidable name of Phototermicoarmillare. It is for collecting any kind of light into a centre for scientific or practical purposes. It has the form of a large desk, composed of several polished rings of copper and white metal, ordered in such a way that each throws the light rays received to another, so that they are united in a large bundle of rays -with considei-able force of projection. In experiments with lamplight, which have been i-epeatedly made with the apparatxxs at Naples, an illumination was obtained from a very weak flame which sufficed, at one thousand metres distance, to enable one to read ordinary print on the darkest night. A propeller screw, singularly original in structixre and theory, has been invented by Dr. J. Collis Browne. It is four bladed, but it would be impossible to convey an idea of the shape of the blades without diagrams. . The effect prodxxced by its revolutions is to eject a rope of water, which is thrown out at right angles in the direction propelled : by which means a maximum pressure is obtained upon the water displaced by the propeller. The direct action of this screw practically serves as a rudder : that is, if the helm is lashed amid-

ships, the vessel will take a straight coxxrse, and pursue that course, without swerving by so much as the fraction of a point, though she be rxmning athwart a cuiTent of any velocity. Fxxrthei*, it has been shown by repeated experiments that this propeller will stop a vessel in her own length : the counter-action being precisely synonymous with the dkect action. In regard to the total solar eclipse of 1876, September 17-18, Nature says:—lts track of totality is wholly upon the Pacific Ocean, aixd iix such course that oixly two or three small islands or reefs appear to be sitxxate near the centi’al line. In New Zealand the eclipse attains a magnitxxde of about o‘s at Auckland, greatest phase at 9h. 18m. a.m.; towards the exti’emity of the Soxxtheni Island, aboxxt Otago, one-third of the sun’s diameter will be obscui'ed about 9h. 12nx. local time. A partial eclipse between similar limits will be visible oix the east coast of Australia and in Van Diemen’3 Laud.

A building, by some thought to be a woollen factory, has been recently unearthed in Pompeii, and contains some grotesque small figux*es of children and other beings on one of its inner walls. An adjacent private house, also l'ecently brought to light, is said to possess some fine wall paintings. A small group of two bacchanal figures, male and female, standing beside a column, is especially noted for its graceful treatment. It is said that henceforth many of the more artistic works will be left where they were found, instead of being transferred to the Museum at Naples. Among the objects so left may be noted a statxxette of a fawn laxeeling, a relief l-epresenting a saci’ifice, and a life-size statue of a draped and veiled woman, styled a “ Vestal Virgin.”

ALCOHOLIC STIMULANTS DURING PHYSICAL EXPOSURE.

Where men are subject to great and prolonged exposure to cold, experience has taught them the danger of taking spirits while the exposure continues. My friend, Dr. Fayer, told me that when crawling through the wet heather in pursuit of deer on a cold day he offered the keeper who accompanied him a pull from the flask. The old man declined, saying, “ No, thank you, it is too cold.” The lumberers in Canada who are engaged in felling timber in the pine forests, living there all winter, sleeping in holes dug in the snow and lying on spruce branches covered with buffalo robes, allow no spirits in their camp, and destroy any that may be found there. The experience of Arctic travellers on this subject is nearly unanimous ; and I owe to my friend, Dr. Milner Fothergill, an anecdote which illustrates it in a very striking way. A pai'ty of Americans ci-ossing the Sierra Nevada encamped at a spot above the snow line, and in an exposed situation. Some of them took a good deal of spirits before going to sleep, and they lay down warm and happy ; some took a moderate quantity, and they lay down somewhat but not very cold ; others took none at all, and they lay down very cold and miserable. Next morning, however, those who had taken no spirits got up feeling quite well, those who had taken a little got up feeling cold and wretched, and those who had taken a good deal did not get up at all; they had perished from cold during the night. Those who took no alcohol kept their heart warm at the expense of their skin, and they remained well; those who took much warmed their skin at the expense of their heart, and they died. But while alcohol is thus injurious during prolonged exposure to cold, the case is very different after the exposure is over, and its administration may then be very beneficial.— Dr. Lander Brunton in the “ Practitioner” for February. ECONOMISING VITALITY. (From the National Food and Fuel Reformer.) It is often a matter of wonder that men in the very prime of life, and endowed apparently with superabxxndant health and strength, suddenly succumb and die when disease fastens upon them ; while life-long invalids, who seem to hold life by the frailest tenure, who are seldom out of the doctor’s hands, and whose first duty in existence seems to be the care of themselves, will continue to live on, and at last reach a good old age. It seems a wonder, we repeat ; but only, after all, to the superficial observer. The man of robust health believes his power of endurance unlimited, while the invalid knows that his only hope of prolonging life is by economising the little vitality that remains to him.

The yonng, in whose veins the blood bounds with a warm, full current, whose muscles long for stretch and play, and whose nerves have not yet been deranged by any of the rude shocks which life has in store for the most of xxs, cannot be easily made to realise that there is entrusted to them only a certain amount of life-force —a soi't of capital in bank for them —and if they draw upon that too rapidly it will all too soon be exhausted. The superabundance of life which presses upon them, and which they shoxxld strive to save for the future, leads them into all sorts of dissipations. The dissapations of the two sexes differ somewhat in character, but their i - esults are all the same. Drinking, tobacco using, late hours, sensational reading—they all exhaust the system, and not only produce temporary derangements, but abstract actual life and strength, which can never be regained, from the individual who is guilty of them. No after care will ever bring back this strength ; it can only preserveandeconomise that which remains.

The besetting sin of the young is the waste of energy and vitality on follies and excitements. As the individual approaches matui-er years he becomes no wiser, since he is apt to be just as spendthrift of his physical and nervous strength by too . close application to business, allowing himself too little time for recreation, and none whatever for rest. Women are even more foolish than men in this particular. Many of them seem to think a peculiar merit attaches to an over-zealous performance of duty, which involves loss of

health and capability for happiness, and sometimes even life itself. They think they are according a woman the highest praise when they can say of her, “ She wore herself ont for her family.” That many women do this there is no doubt. They may not all actually die, but they live a sort of dead-and-alive existence, knowing nothing and caring for nothing but that their daily round of drudgery shall be faithfully performed. They are old and decrepit in body while yet they should be feeling somewhat of the freshness of youth. Constant application to merely manual labor gives them no opportunity for cultivation of mind, and they remain children in intellect, or rather dwarfs, since a child’s mind is characterised by a freshness of thought and an eagerness after thought that these women never know. Scholars are peculiarly liable to waste their powers in too prolonged mental exertion. It was said of the late Vice-President of the United States, that if he had been content to have allowed himself more rest from the tasks which absorbed him, he might have survived for years. But he gave himself no relaxation, and he had to pay the penalty. Both the mind and body of men are so constituted that they require constant but varied action. Utter idleness, of either body or mind, unless they be in a more or less diseased state, is not only unnecessary, but harmful in the extreme. It is a habit which, once indulged in, will grow upon the individual. Change of occupation for the muscles, change of the current of thought for the brain, is what will promote the fullest and most healthful development of both. Wo have the almost universal spectacle of men in our factories and shops all over the land, devoting ten hours a day to a single employment. But in most cases this employment is so varied in its nature that it calls into play different sets of muscles, allowing one to rest while another is active. Then there are the remaining hours of the waking day, giving opportunity . for recreation. Still, there can be little doubt that, if it could be so arranged that labor should be performed with more frequent intervals for rest, or so that the labor itself should be more diversified, workmen would not so soon break down, and the ratio of life among these classes be prolonged. But the man "who spends ten hours a day at mental labor must do it at his peril. There can be no doubt whatever that he is shortening his life thereby, or, what is even more to be dreaded, hastening a decay of his mental powers, while his physical will still remain in tolerable vigor. The exceeding prevalence of paralysis, and a kindred class of diseases, has been remarked of late, and it is said by physicians that they are occasioned by a too lavish expenditure of the vital powers, induced by the high pressure manner of living, working, and thinking, which is peculiar to us as a people. The only way in which the vital forces can be properly economised is by keeping all the powers of the mind and body constantly employed, but employed in such a manner that there shall be no prolonged strain anywhere. There is no more significant word than “recreation.” It means literally re-creation —a building again of the exhausted tissues of the body and brain. Recreation does not mean idleness, and it may mean labor. A wise man will so arrange his labors that each succeeding one shall be so totally different from the last that it shall serve as a recreation for it. Physical exertion may follow mental, and then give place to it again. A man equally "wise in all hygienic measures, who could nicely adjust the labors of mind and body in their true proportions, might hope to attain old age with all his mental faculties fresh and vigorous to the last.