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Page:Popular Science Monthly Volume 18.djvu/300

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THE POPULAR SCIENCE MONTHLY.

its surface is 212 metres (689 feet) below the level of the Mediterranean, and that its greatest depth, which is at the northern extremity opposite the upper mouth of the Jordan, is 250 metres (812 feet). On both shores of the lake are terraces covered with rounded pebbles, rising to a height which indicates that the level of the lake was once the same as that of the Mediterranean. He believes that the waters of the lake were formerly very salt, more so than sea-water, but not so excessively salt as the waters of the Dead Sea, and that they have been freshened since the level of the lake was lowered by volcanic convulsions, by the flow of the Jordan, till they have become drinkable.

Professor Schneltzler, assuming that the color of flowers is due to the combination of different chemical elements in their tissues, has shown by experiment that when an alcoholic extract of the color is made it is enough to add to it an acid or alkaline substance to cause it to exhibit any of the colors which plants present. Flowers of the peony, for example, give a violet liquid in alcohol; if salt of sorrel is added to this liquid, it will turn a pure red; soda produces, according to the quantity that is added, violet, blue, or green.

Those in pursuit of the marvelous may learn a grain of caution from the following, taken from an article on "Living Toads in Stone" by Mr. Thomas G. Denny, in a recent number of "Science Gossip": "Most of us have heard of 'Flint Jack,' but I do not think many readers of this journal have met with any manufacturers of fossil toads; but I knew many years ago a working naturalist living in Leeds who used to prepare for sale toads, stated to have been found in beds of coal, by baking them perfectly black and hard in an oven, and then taking square pieces of coal and, after splitting them carefully, he would cut a hollow in each portion to receive the 'ancient reptile.'"

Mr. Frederick Ransome has succeeded in producing a good hydraulic cement from the slag of blast-furnaces. His process, which is applicable to almost any quality of slag, has the advantage over previous methods of making cement, that while in them the materials, lime, silica, and alumina, had to be brought together and carefully combined, in blast-furnace slag the combination has already been completely effected before the slag has left the furnaces, and generally with the proportions of silica and alumina that are required. By mixing the slag with an additional quantity of lime and calcining the mass, a strong and reliable cement of an agreeable color is produced.

It has been affirmed, in proof of the theory that fat is formed from albumen, that the albumen of the cheese in the cellars of Roquefort is changed to fat by the action of a fungus found there. The assertion is disproved by experiments made by Herr Sieber on the cheese in these cellars, which show that the most marked change that cheese undergoes in ripening is the loss of water, and that the proportion of fat remains unaltered if only the dry substance be considered. A decomposition of the albumen also takes place, the caseine passing into a series of decomposition-products which are similar to products of putrefaction in the first stage of putrefactive fermentation, but the analyses show no transformation of albumen into fat.

Efforts to reduce monkeys to discipline have not very often been successful. A native of the province of Bengal has, however, trained several of them to work the cords by which the punka, or ventilating fan of India, is moved. They perform their task to perfection, and, thanks to their activity, keep the punkas in continuous motion, maintaining a constant, agreeable movement of air all through the room.

Dr. Henry Barnes records a case of an extremely severe attack of gout brought on by sleeping in a newly painted room. Three years before, the patient, an old man, had suffered a slight attack of the disease (the first of his life), but soon recovered, and, up to the time of this exposure, had been quite free from gouty symptoms. The introduction of lead into the system is given as the cause of the attack.

A company with large capital has been formed in Paris to work up an invention for coating thread with silk. The invention embraces, according to the "Bulletin des Soies," a chemical process for covering linen or other vegetable threads with amesh of silken matter in a manner similar to that in which metallic objects are plated with gold or silver. The process is dependent on the fact, which has long been known, that silk is soluble in several strong acid preparations.

The French Chamber of Deputies has voted a credit of fifty thousand francs to M. Pasteur to enable him to extend his researches upon the contagious diseases of animals. The labors of M. Pasteur during the last four years have already led to the discovery of the causes of carbonaceous affections, and the knowledge thus gained has been employed to prevent them in many cases. His present investigations are in relation to the character of virulent maladies in general.