SCIENCE.

New Zealand Times, Volume XXIX, Issue 4292, 22 December 1874, Page 3

SCIENCE.

Etching.—Mr. Hayllar has discovered that it is possible to substitute glass for copper, and thus obtain an etching at much less cost than has been possible, hitherto. Copper, too, being opaque, the engraver could not ascertain how his work was progressing, except by taking proofs. But now he is able to see at once what progress he makes, and to.repair any defects as he goes on. Mr. Hayllar has recently left Saxmundham to reside permanently in London. Fireproof and Unalterable Colors.—Dr. Kosch, of the Chemical and Technological School at Vienna, has made an interesting discovery, which consists in the fact that certain colors may be made fireproof, and may thus be used for painting on china in precisely the tones required. The inventor has prepared a palette on which his colored enamels may be used like ordinary oil colors, and may be painted in every conceivable combination of tints without being in the slightest way altered by the action of fire. Dr. Kosch at the same time makes use of a specially-prepared enamel, which he spreads oyer the surface to be painted on, and by which the irregularities and porosities of the porcelain arc as thoroughly concealed from view as if they were covered with thin smooth linen. The importance of such a surface medium will be fully understood by all Who are practically conversant with the difficulty of preventing the irregular and undue absorbtion of color which has hitherto stood in the way of producing artistic and carefully toned effects of color on porcelain. Another and scarcely less interesting invention for which Austrian art is indebted to Dr. Kosch, is the fusion of gold, silver, and platinum with bronze, by which the most gorgeous effects are produced. The Altitude at which Men can Live. —There has been a great deal of discussion, says Chambers’s Journal, as to the altitude at which human beings can exist, and Mr. Glaisher himself can tell us as much about it as anybody. In July, 1872, he and Mr. Coxwell ascended in a balloon to the enormous height of 38,000 ft. Previous to the start, Mr. Glaisher’s pulse stood at 76 beats a minute, Coxwell’s at 71. At 17,000 ft. the pulse of the former was at 81, that of the latter at 100. At 19,000 ft. Glaisher’s hands and lipsiwere quite blue, but not his face. At 21,000 ft. he heard his heart beating, and his breathing became oppressed ; at 29,000 ft.. he became senseless ; notwithstanding which the aeronaut, in the interest of science, went up another 8000 ft., till he could no longer use his hands, and had to pull the strings of the valve with his teeth. Aeronauts who have to make no exertions have, of course, a great advantage over members of the Alpine Club and those who trust their legs ; even at 13,000 ft., these climbers feel very uncomfortable, more so in the Alps, it seems, than elsewhere. At the monastery of St. Bernard, 8117 ft. high, the monies become asthmatic, and are compelled frequently to descend into the Valley of the Rhone for—anything but a breath of fresh air ; and at the end of ten years’ service are obliged to give up their high living, and come down to their usual level. At the same time in South America there are towns, such as Potosi, placed as high as the top of Mont Blanc, the inhabitants of which feel no inconvenience. The highest inhabited spot in the world is, however, the Buddhist cloister of Hanle, in Thibet, where twenty-one priests live at an altitude of 16,000 ft. The brothers Schlaginsweit, when they explored the glaciers of the Ibi-Gamin in the same country, encamped at 21,000 ft., the highest altitude at which a European ever passed the night. Even at the top of Mont Blanc, Professor Tyndall’s guides found it very unpleasant to do this, though the Professor himself did not confess to feeling so bad as they. The highest mountain, in the world is Mount Everest (Himalaya), 29,003 ft., and the condor has been seen “ winging the blue air ” 500 ft. higher. The air, by the bye, is not “ blue,” or else, as De Sausser pointed out, “ the distant mountains which are covered with snow would appear blue also;” its apparent color being due to the reflection of light. What light can do, and does, is marvellous ; and not the least is its power of attraction tolhumanity.