SCIE.tifIC AND USEFUL

New Zealand Mail, Issue 1679, 4 May 1904, Page 72 (Supplement)

SCIENTIFIC AND USEFUL

THE LONDON “TUBES.” London lias now four tubes for underground electric railways in full working operation. The latest line, the Great Northern and City, has now finally completed its ’signalling apparatus' to tlie Board of Trade’s satisfaction, and has been running for some time. The next great event for underground London will be the completion of the electrification of tlie Metropolitan and District, which may or may not be this, year. Another notable recent event has been the running of experimental electric trains over eight miles of * tlie NorthEastern Railway near Newcastle. During tlie last two years this railway lias lost 61 per cent of its Passenger traffic ill that locality through the competition of electric tramways, so that it is certain that this work will be pushed along. Drivers are now being trained on tlie Lancasliiro and Yoiltsliiio section, between Liverpool and Southport, so "that in all probability we shall see that line in operation by electricity and in full working order very soon. In America the transition from steam to electric railways is taking place with the feverish activity common to that country '; but doubtless both England and the States will profit by the experience gained in working railways by electricity on the Continent.—“ English Mechanic.” MARS., ' - Mr Denning lias published the results of his observations on the planet Mars during 1903. The streaks, or canals, on the planet’s surface appeared to be, without doubt, objective features, but no “doubling” was observed. Decided changes were observed to take place in the appearance of some of the markings, but Mr Denning attributes these apparent changes, to the drifting of vaporous condensations over the permanent markings rather than to any real modifications of the latter. Many brilliantly luminous areas were observed, and although thej exhibited decided changes, Mr Denning believes them to be permanent features, and urges that more definite observations of their latitudes and longitudes should be made and recorded. A curious feature of these bright markings is that they appear brighter when on the edge of the planet’s disc than they do at its°centre, behaving, in this respect, like faculae on the sun’s disc. One rotation period for the planet satisfies the observations of all the markings, thus proving them to'be definite features of the planet's surface rather than drifting vapours such as are seen when observing Jupiter and' Saturn. A BREATH OF COLD AIR. A well-known medicai man, Dr. H. D. Bartlett, recently pointed out that the volume of air is reduced one-five-hund-redtli part fo reach degree of reduction in temperature. Now (says “Science Siftings”), if we consider the difference in temperature on a hot summer's day

compared with the temperature taken on a cold day in winter, there will be a difference of 50 or GO degrees. Therefore, a person breathing in the cold air would obtain as much oxygen in six breaths as he would in seven breaths taken in hot weather. Thus it will be seen that cold, pure air gives one-seventh more oxygen than ordinary mild air. This increase of oxygen is a matter of great consequence to the sufferer, and not only to the sufferer but also to the person enjoying good health. That is why one feels better after a sharp on a crisp winter morning than after* a stroll in - summer. There is, especially, no bettor breakfast appetiser than an early morning walk in the frosty weather. The mere fact that a fire burns brighter in winter than in summer is because of the increased amount of oxygen in the air. AN ANCIENT FISH. Amongst the most ancient animals still inhabiting our planet is the so-called, mud fish of Africa. This creature is worthy of respect, if only in consideration .of its antiquity, which dates far back in the early ages of the world. The most striking feature of the mud fish is the possession of lungs as .well as gills. On the approach of the dry'season, in its natural haunts in Central Africa, it hollows a chamber in the mud'and enters upon' a rest extending over many months, during which time it is without access to water, and breathes only air. While in the mud these creatures may be dug up and survive even after a journey across the world in this dry state. Professor Denny received one of those mud blocks not long ago. In the presence of the students the hard block was placed in warm water and after being thus exposed for nearly two'hours the fish, which went to sleep in tropical Africa many months before, awoke-and displayed considerable activity. WHEN TEA WAS FIRST USED. ' \ Neither Mr Hugo Young nor Miss Marie Corelli was quite accurate in the date as- to the first use of tea' in Britain. It was some years before the time of Queen Anne —namely, in the year 1657 that tea began to be used as a national beverage, when Garraway opened a tea-house in Exchange Alley, the price then being from £lO to £5 per pound. Pepys, wrting on September 28th, 1660, says v—"l did send for a cup of tee (a Chinese drink), of which I had never drank before.” Two years later he wrote:—“Home, and there find my wife making of tee, a drink which Mr Polling, the Pothicary, tells her is good for her cold.” 'ln 1678 the East India Company imported 47131 b; in 1725, 370.3231 b was drunk in England; in 1740 the prices ranged from 7s to 24s a pound.—'Alliance News.” } THE BLIND AS MASSEUSES. The practice of teaching the blind massage as a means of earning tlieir living is making rapid strides, and one of their number lias just completed a translation of Mrs Creighton Hale’s well-known work, "The Art of Ma'ssage,” into the Braille type. It has been found that not only do blind people learn with a rapidity which leaves ordinary pupils far behind but their highly-developed sense of touch gives them a power not possessed by those in full enjoyment of the other faculties. One of the best known surgeons in London makes a point of employing- blind masseuses for his most important cases, while they are in great demand to fill permanent posts at hydropathic establishments, as at Harrogate, Brighton, and many other resorts frequented by invalids. FRUIT GRAFTING. It is a well-known fact that the branches and buds of fruit, and other trees, can be grafted on to other trees, but two French horticulturists have actually been experimenting with the grafting of the fruit itself. They took a pear, when "thinning out” the fruit, and. by the process known to gardeners as grafting under the bark, bound the stalks of the pear to a twig of another tree and then gummed the whole over. Naturally, some sap was lost in the process, hut the fruit, although smaller in size, eventually ripened. Should the process become a success, it will be of great use to gardeners, for they could then graft the excess of fruit on one tree, on to another which was not so prolific. As it is at present, all the young fruit thinned out has to be thrown away. TO IMPROVE BRITAIN’S* CLIMATE. A suggestion has been made by Mr J. H. Knight, or Barfield, in order to change Britain’s climate-. He would have trees planted in all available spaces in the west and South of Ireland, and in parts of Cornwall; and he believes that in 15 or 20 years these trees would draw much of the rain from the clouds coming from the Atlantic, causing the interior of the country to become drier. The winter, would, perhaps, become a little colder, though not' with the present damp cold. A similar forest was planted 150 or 200 years ago along the coast of France to stop the inroads of sand, and now serves as an effective barrier for more than 100 miles. KEEPING NEGRO CHILDREN WHITE. Dr. J. W. Hill, of Indiana, proposes to prevent infants born of negro parents from turning black, just as you would develop a photograph by red light. An expectant negro mother has consented to ,aot as patient. She is to remain in a room furnished in red. lighted by red, and will be ministered to by physicians and nurses dressed in red. 'Dr Kill seems to believe that the negro skin like an unexposed chloride of silver surface — keep it under red light and it will not turn black. It is not stated how long the baby is to be kept under this protection*