The Arkansaw traveler., 1886-04-03
Compiled for The ATkaHsow Trareser. SCIENTIFIC MISCELLANY.

nut, sixty-four; blue, eleven; and gray eyes, three per cent.
 Dr. Burney Yeo, of London, reports the curious observation that there are persons who usually drink tea without injury, but in whom, when in a depressed mental condition, it occasions indiges- ton and palpitation of the heart.
 Exact measurements of the oscilla- tions of chimneys have been made. One near Marseilles, France-ll5 feet high and four feet in external diameter at the top-reached maximum oscilla- tion of twenty inches during a high wind
 Dr P Andries finds that the danger of & house being struck by lightning has increased three to five fold in Ger many within the last fifty years, and sup poses this to be due to the impurities from the ever increasing number of chimneys
 Prof. l.. Weber mentions a stroke of lightning in Germany which broke a window-pane and forced jet of water through the aperture upward to the ceil- ing, part of which it detached. Three buck etfuls of water were afterward taken from the room.
 The principle of telescopes was de scribed by Roger Bacon about l250, and is said to have arranged glasses so that he could see very distant objects. Cali leo constructed telescopes in 1909, and discovered Jupiters satellites in l6l0.
 The average height of Europe has been estimated by German geographer to be 974 feet Switzerland shows the greatest mean height, 4624 feet, and the Netherlands the least, 3l feet Inter- mediate arc Spain and Portugal, 2,24S; Austria, 1898; Italy, 1896; France, l ,292 British Islands, IA; Germany, 70l Russia, 54S; Denmark, ll5.
 The time required for the develop ment of smallpox after exposure to it is very difficult to determine, but is usually supposed to be from twelve to fourteen days. Prof II. Eiehorst of Zurich, has, however, at length succeeded in recording three cases in which the incubation period is clearly known, and finds it to be a little more than nine days in each case.
 Arsenic and Malaria. s. II. Davey of Cornwall Eng, confirms Dr. Tomma- si-Crudelli's opinion concerning the eff feet of arsenic in preventing cholera and other zymotic diseases. Although dur ing the last forty years many cases of cholera, fever, smallpox, etc, have oc- cured in the country surrounding the extensive arsenic works at Bissoe, not a single case has been known within about two miles of the source of the deadly fumes
 Photographic Progress.-The possibil- fly of photographing in the dark has been shown by Abney, an English ex- perimenter He has succeeded in pre- pairing plates which are sensitive to the rays lying beyond the red end of the spectrum-the dark heat rays-and with such plates used with rock salt lens it should be possible to photograph bodies having high temperature, al- though that temperature may be far be low that necessary to render them self luminous.
 Limit of Hearing It has been found by Dr. Tait that the ear in women can perceive higher notes-that is. sounds with a greater number of vibrations per second-than the ear in men The highest limit of human hearing is some where between II ,0O0 and 42000 vibra- tionS per second Few persons have equal sensibility to acute sounds in both ears, the right ear usually hearing a higher note than the left. The low est continuous sounds have about six teen vibrations per second.
 Restoration of Sight-One of the marvels promised at the present day, with good prospect of realization is that the blind shall see. Already has such partial success attended the substitution of perfect rabbit eyes for imperfect hu- man ones that the process of eye-graft- ing seems likely soon to become a prac- tioai reality, But there are many eyes which Dr. E. Martin, of Marseilles, has now discovered may be readily repaired In very large proportion of cases blindness proves to be due to opacity of the cornea, and when this alone is the cause Dr. Martin accomplishes the mir acle of restoring sight bv inserting into