Page:Popular Science Monthly Volume 15.djvu/442

 accordingly considered the star to be a fifth satellite of Jupiter. The statements contained in his letter agree sufficiently with the assumption that the star was or is a variable fixed star, and the diagrams and descriptions indicate that the conjunction of Jupiter and of the star occurred on April 7th. By means of the geocentric place of Jupiter computed for the date, Winnecke has been enabled to identify the observed star with Lalande's 18,886, a star of the eighth or the seventh to eighth magnitude, which, during the last half century, seems to have varied little in brightness. Variable stars, in the sense of the term as now used, were unknown in Schemer's time, and his description of the rapid decrease of the star's light carries with it some proof of its truthfulness. The spectroscopic observation of this star, with sufficiently powerful instruments, would be very desirable. Its place for 1855, date of the Bonner Durchmusterung, is right ascension 9h. 29m. 21·2s., and declination +15° 52·1′.

Identity of Heat and Light.—In a recent lecture, Mr. W. H. Preece, the English electrician, made the following interesting remarks on heat and light: "These two," he said, "are identical in character, though different in degree; and whenever solid matter has imparted to it motion of a very high intensity—in other words, when solid matter is raised to a very high temperature—it becomes luminous. The amount of light is dependent on the height of this temperature; and it is a very remarkable fact that all solid bodies become self-luminous at the same temperature. This was determined by Daniell to be 980°, by Wedgwood 947°, by Draper 977°; so that we may approximately assume the temperature at which bodies begin to show a dull light to be 1,000°. The intensity of light, however, increases in a greater ratio than the temperature. For instance, platinum at 2,600° emits 40 times more light than at 1,900°. Bodies when raised to incandescence pass through all stages of the spectrum; as the temperature increases, so does the refrangibility of the rays of light. Thus, where a body is at a temperature of 250°, it may be called warm; at 500°, hot. At 1,000°, we have the red rays; at 1,200°, the orange rays; at 1,300°, the yellow rays; at 1,500°, the blue rays; at 1,700°, the indigo rays; and at 2,000°, the violet rays. So that any body raised to a temperature above 2,000° will emit all the rays of the sun. Inversely, the spectroscope may thus be enabled to tell us the temperature of the different lights, and it is perhaps because some lights do not exceed 1,300° that we have all the rays beyond the yellow."

A Horse with a Load in his Stomach.—Dr. Albin Kohn recites in "Die Natur" the particulars of the sudden death of a horse, caused by the presence of a stony concretion in the animal's stomach. The horse was to all appearance perfectly sound and well one morning when carrying his master about his estate, when suddenly he fell dead. A veterinarian opened the carcass to ascertain the cause, and found in the abdominal cavity a stone of about eight pounds' weight, and in the wall of the stomach a hole of corresponding size. The stone was submitted to Dr. Peters, of Posen, for analysis, who first cut it into halves. Each half of the rather round stone—called by Dr. Peters "magenstein," i. e., stomach-stone—looked very much like a Chester cheese. The diameter of the cut surface was from 15 to 17 centimetres, and concentric rings are visible in it. At the center its texture is radiate. Dr. Peters supposes the animal at some time swallowed a fragment of millstone, and that around this nucleus numerous layers were afterward deposited. Externally the stone is smooth, rather hard, and of a grayish-yellow color; its composition is: ammoniomagnesic phosphate 87 per cent., organic matter 6, water 1, silicic acid 1; other salts per cent.

"Jumping Frenchmen."—It is a very instructive narrative which Dr. G. M. Beard publishes of the doings of the "Jumpers" of the woods of Maine and Canada. These jumpers are mostly half-breed French-Canadian lumberers who have acquired the permanent habit, which they can not control, of jumping or striking out with their hands, when commanded to do so by any one who chances to lie near. The habit appears to have been acquired, in the first instance, by tickling one another in the winter camps