Page:Popular Science Monthly Volume 20.djvu/445

Rh experiments instituted by M. Pictet to determine the density of liquid oxygen, hydrogen, and nitrogen, have been followed up by Messrs. Gailletet and Hautefeuille, who have facilitated the processes by previously mixing the gases with carbonic acid and protoxide of nitrogen, whereby the liquefaction is made to take place more readily. The density of the liquids of the latter gases being known, it is easy to compute that of the substances under examination. The results of tests made at a very low temperature are favorable to the theory of the relations that have been suggested between hydrogen and magnesium, oxygen and sulphur, nitrogen and phosphorus; but, as the freezing-point of water is approached, discrepancies are manifested which grow more and more accentuated.

of Rheims, reports that he has discovered that the tincture of ergot of rye associated with phosphate of soda produces on those to whom it is administered an hilarious excitement, similar to that which is brought on by laughing-gas.

in a communication made recently to the French Geographical Society, on his journey to Timbuctoo, says that in the Inguidi, a region of sand-dunes, he observed the equally rare and interesting phenomenon of resounding or musical sand. "All at once," he said, "there was heard in the desert, issuing from a dune of sand, a prolonged, muffled sound, quite like the sound of a trumpet. It continued for some seconds, then ceased, to be resumed in another direction. The phenomenon made the traveler anxious. I suppose it was occasioned by the friction upon each other of the burning grains of quartz, which are simply placed one by the other, and are continually in motion."

has shown that the electrical qualities which are already plainly perceptible in most kinds of paper can be greatly increased by subjecting it to a previous treatment. Common unsized paper, Swedish filtering paper, or silk paper, when dipped in a mixture of equal volumes of nitric and sulphuric acids, washed and dried, becomes imperfectly transformed into pyroxile, and extremely electric. When put on a wooden table or an oil-cloth, and rubbed with the hand, it will immediately attract light bodies; if taken up from the oilcloth in the dark, the whole surface shines like phosphorus; when the finger is brought toward it, it gives off a spark. A Leyden-jar may be charged with it. It gives off, when rubbed, the characteristic odor of ozone. It preserves its properties for a long time, and may have them restored by heating it. Thus, for a few cents, we may possess a machine competent to aid in the illustration of all electrical phenomena.

of Newcastle, in a paper on the geological distribution of endemic goitre in England, has shown that the conditions of the prevalence of this disease are substantially the same as they have been shown by the researches of Dr. de St. Lager, of Lyons, to be in France. In both countries the formations in which the most goitre is supported are both calcareous and metalliferous. Metalliferous impurities alone do not promote the disease, for the Devonian and granitic formations are free from it. The absence of limestone alone does not prevent it, for it exists on the lignitiferous beds of France, and the ferruginous sands of the weald. Dr. de St. Lager believes that endemic goitre coincides with metalliferous deposits, of which iron pyrites is most active.

describing the Canidæ of the Loup Fork, or highest Miocene formation of the West, represents that the number of species is not so great as in the preceding periods of the Miocene, while those that are known more nearly approach the existing dogs in character, and are of a larger average size.

and Professor G. Forbes have made some new researches to measure the velocity of light, by the method that was employed by M. Fizeau and M. Cornu. The electric light was used, with two reflectors a quarter of a mile apart, and a revolving toothed wheel was employed to alter the intensity of the reflected light. Through this two stars of light were seen, one increasing, the other diminishing in intensity as the speed of the wheel was increased. The speed required to produce equality of the light was determined by means of a chronograph. The final result of the mean of the several observations for the velocity of the light from an electric lamp in vacuo was 187·273 miles a second. The observations on the color of the stars indicated that the blue rays travel faster than red rays, with a difference equivalent to about 1·8 per cent, of the whole velocity.

of Geneva, announces the discovery of a method of construction for greatly increasing the speed of vessels by making such an arrangement of the keel as will diminish the resistance of the water to the lowest point. Where it is applied, the prow, instead of sinking deeper as the speed increases, will be raised, and only the sides of the hull and the neighborhood of the wheel will be exposed to the friction, so that the vessel will glide over the water instead of having to push its way through it. Professor Pictet expects to attain a speed of from thirty to thirty-six miles an hour. A vessel embodying his plans is building for Lake Leman.