SCIENTIFIC AND USEFUL.

New Zealand Graphic, Volume X, Issue 16, 22 April 1893, Page 368

SCIENTIFIC AND USEFUL.

CAUSE OF SUN SPOTS. No generally accepted theory of the cause of sun spots has been put forward, but there are many facts which seem to link them with volcanic outbursts through the photosphere of the sun, and that when this force is spent the liquid photosphere flows over and hides the place. There are many features difficult or perhaps impossible to explain upon this theory, but perhaps not so many as beset other theories, and by general consent the cause of sun spots is admitted to be still a matter tor investigation. THE EXTENT TO WHICH STEAM IS HELPING MAN’S WORK. A German authority states that four-fifths of the steam engines of the world have been constructed within the last quarter of a century. The total horse-power of these engines is estimated at 49,000 000, of winch the United States takes the lead with 7,500.000 horse-power; Great Britain, 7,000,000 ; Germany, 4,500,000 ; France, 3,000,000 ; and Austria, 1,500,000 Considering that the horse-power of an engine is equivalent on an average to the power of seven men, the world’s steam engines represent the energy of 1,000,000.000 men, or double the number of workers in the world, the total population being estimated at 1,460,000,000. CHIEF STAPLE OF PAPER. Pulp made from wood is the chief staple of paper at the present day. Eighty per cent, of the paper used for periodical literature is said to have this material as its basis. Some idea of the immense quantities of wood used in this way may be gathered from the fact that the Petit Journal, which is printed on wood pulp paper, and has a circulation of over a million copies a day, consumes 120,000 fir trees, of an average of 66ft. .every year. This is equal to the yearly thinning of 25,000 acres of forest. And this immense quantity of wood goes to form the raw material for a single periodical only. In Austria, Germany, and Sweden, which are the great centres of wood pulp production, the destruction of forests is becoming a matter for grave consideration, as, unless some other material comes into use, the forests of Europe will have fallen a prey to the insatiable appetite of the printing press, and disappear from the face of the earth. CORROSION OF LEAD PIPES AND COVERED CABLES. It has been known for many years that lead pipes frequently suffer from corrosion when laid in certain kinds of earth, while certain waters eat away the inside. During the discussion on a paper on ‘ Cables.’ at a meeting of the students of the Institution of Electrical Engineers, Mr A T. Weightman mentioned the case of the Loch Katrine water at Glasgow. He stated that this water contained free carbonic acid which attacked the lead, and that the fault was corrected by treating the supply with chalk. He proposed therefore to embed lead-covered cables in chalk. Whether this would act or not depends, of course, on the particular soil in which the cables are laid, but the scheme would cost very little, and it might be well worth while trying the experiment. AN ELECTRIC SPRING. In many parts of the world are ‘ mineral ’ springs which are supposed to have wonderful life giving properties Bonce de Leon explored Florida in seat ch of a spring of eternal youth, and the waters of some other springs are supposed by many persons to be hardly less wonderful than Ponce de Leon’s spring would have been had he found it. The Electrical lieview describes the latest device for working miraculous cures by means of water: ‘lt was but a plain mineral spring, but thecups that the patients drank from were fastened by a brass chain to an iron bar which enclosed the mouth of the bubbling spring. You were prevented from coming too close by another circular iron railing about eight feet across. The ground around the spring was naturally moist, and it was either this ground or the iron which was one of the ends of an open electric circuit. The cup held by the chain was the other end. The person drinking simply completed the circuit through the body, and when he bad finished, the attendant kindly and immediately removed the cup from his hand. The drinkers always felt that “ delightful tingling sens .tion,” and rejoiced that they had found the fountain of youth. Some imagined they even felt the new blood coursing through their veins. A small induction coil ingeniously concealed and connected with the cup and railing was a cheap method for producing that “ invigorating feeling.” ’ °