The passage of trains curiously affects the magnetic and electrical measurements of the Montsouris Observatory, at Paris, Trains on the Ceinture railway, sonic 70 yards distant, produce movements of the bifilar magnet so regular that the exact tinto of the passages can be told from the regis tered oscillations, The effect is due to the fact that the wheel-tires of the cars become magnetised, and strongly attract the magnet, An equally remarkable phonomenon is observed when an engineer of the Sceaux railway, about 90 yards away, blows off steam, the electrometer being partly discharged, and indicating that the electric potential of the air is lowered about one half.
The basis of the French system of identifying criminals from prison records, as oxplained by M. Bertillon, is the keeping of act rate measurements of the bony parts of the body, which change little after maturity, These parts are the head, the fuct, the middle finger, and the extended fore-arm. Photography is used only as an aid, and from many thousands of photographs it is easy by these measures to find whether one exists of any individual, the photographs or descriptions being divided into the three classes of tall, medium and short persons, subdivided into classes of long, medium and short heads, again subdivided according to the width of the head, and so on, It 90,000 photographs of criminals have boon thus classified, a small group of some 15 correspond measarenient to any suspected person may be quickly selected, when complete identification is easy. Cri: minals may be recognised many years after measurement, and even, by their skeletons, long after death.
a new electrical lantern, Professor Strickler, of Vienna, uses an ingenious combination of lenses which projects the magnified images of objects on a white screen in their natural colours. A pimple, for instance, can be shown in its real appearance to a large class of students.
ests of the advantages of oxygenated oil gas have been instituted by the Brin's Oxygen Works, of London. It had been shown before that mixture with oxygen greatly increases the illuminating power of coal gas, and the same proves to be true of oil gas, to which, as is further shown, as much as 50 per cent. of oxygen may be added without risk of forming an explosive mixture. The present process of manufacture consists in first heating American petroleum to a moderate temperature in an bron retort, and then adding to the gases and vapours produced about 20 per cent. of oxygen. This prevents the subsequent condensation of the vapours, and at the same time enormously increases the illuminating power. The necessary plant is simple, and the experiments indicate that an illuminant of higit intensity and low cost may be advantageously produced on a large scale.
of Venezuela in the days before Columbus An interesting glimpse of the metallurgy has been giver by a French chemist. Analyses were made of three metal trip kets found near Caracas in some earthern sarcophagi containing bones. One of these trinkets was probably hammered from native gold containing silver and copper; but the other two are alloys of ntiferous gold with a product of the reduction of an ore of copper and iron. Near the site there occurs a vein of copper carbonate mixed with iron oxide, but cou-taining neither gold nor silver.
Text read from the printed page and cleaned; old type leaves the occasional error.