Page:Popular Science Monthly Volume 10.djvu/785

Rh prehistoric vestiges of Colorado." Captain Berthoud believes, from his observations, that man existed in the Rocky Mountain region prior to the deposit of gold in the Colorado mountain-slopes, Creek, Bar, and Placer diggings, about latitude 39° 30' to 41° north. Captain Berthoud has not only found flint tools and chips in the gold-bearing glacial drift, with remains of fossil elephants, but also in the drift of older date below this gold-bearing drift. Flint tools have been also found in company with estuary shells of not later age than older Pliocene as determined by Prof. Conrad.

The Decline of Savage Races.—Virchow, in an address upon the present position of anthropology, makes a few very just observations upon the subject of the decline of savage races in the presence of civilized man. Thus he remarks that we must not, in the case of an entirely isolated people, judge of their capacity for culture from the signs of it which exist. The extinction of uncultured races, he thinks, is rather to be ascribed to the barbarousness of Europeans, and to their incapacity to educate savages. There is no evidence that uncivilized races must become extinct—indeed, the contrary is proved by the history of Europeans themselves. If the civilized people of the present day are the product of a higher development, we cannot regard the possibility of such a development as a cause of the extinction of races in the same stage of culture once occupied by ourselves.

Estimation of Alcohol in a Watery Mixture.—Dr. Werner Siemens has designed an ingenious apparatus, by which a stream composed of alcohol and water, mixed in any proportion, is so measured that one train of counter-wheels records the volume of the mixture, while a second counter gives a true record of the amount of absolute alcohol contained in it. The principle is described as follows: The volume of liquid is passed through a revolving drum, divided into three compartments by radial divisions, and not dissimilar in appearance to an ordinary wet gas-meter. The revolutions of this drum produce a record of the total volume of passing liquid. The liquid on its way to the measuring-drum passes through a receiver containing a float of thin metal filled with proof-spirit, which float is partially supported by means of a carefully-adjusted spring, and its position determines that of a lever, the angular position of which causes the alcohol-counter to rotate more or less for every revolution of the measuring-drum. Thus, if water only passes through the apparatus, the lever stands at its lowest position, and then the rotative motion is not communicated to the alcohol-counter, and this motion is rendered strictly proportionate to the alcohol contained in the liquid, allowance being made in the instrument for the change of volume due to chemical affinity between the two liquids.

Preservation of Iron against Rust.—We find in Van Nostrand's Engineering Magazine an account of Dr. William H. Sterling's process for preventing the rusting of iron. The principle of this system, we are informed, consists in the saturation of the iron with a non-oxidizing or non-oxidizable substance while the iron is in a properly heated and expanded condition, produced by heating in a vacuum or in a simple chamber. One method of applying this system is given as follows by the inventor: "A vessel of iron, or any suitable material of sufficient strength, is made in the form and size best adapted to the shape and dimensions of the iron which is to be treated, with the lid so constructed that the vessel may be closed hermetically, and at the bottom suitable pipes are arranged for conveying steam and water alternately, for the purpose of heating and cooling the interior." Suitably connected with this vessel is a power-pump to produce the necessary pressure, also appliances for obtaining a vacuum. The iron is now heated to the desired degree and placed in the vessel, the top closed hermetically and superheated steam turned into the pipes at the bottom, to keep the metal at the required temperature; at the same time an atmospheric vacuum is produced by an ordinary air-pump connected with the chamber; the proper quantity of pure paraffine, having been also previously heated, is now let into this chamber and forced under pressure into