Page:Popular Science Monthly Volume 32.djvu/733

Rh exercise of extreme care. It is practically observable that whoa nutrition is impaired in a nerve-center or branch, extreme difficulty is met in restoring the integrity of the nervous function, and even the wear and tear cf ordinary life seems to increase the exhaustion instead of reducing it by stimulation of the recuperative faculty.

Handiwork-Teaching in Swedish Schools.—Slöjd is the Swedish name for handiwork instruction in the schools. It was invented by the famous Finnish educator Uno Cygnæus, and was adopted in Sweden about fifteen years ago. The teaching is confined to simple work in woods, if it is regarded merely as a training for the faculties, or in many branches if it is to be regarded as subsidiary to technical instruction. No efforts are spared to make the system attractive to pupils and parents. Pupils arc allowed to keep what they have made, or to buy it cheaply; or are credited with deferred pay, which they forfeit if they leave before a stipulated course is completed, or which is given them as credits in a bank-book on finishing the course. The sympathy of parents is catered to by teaching the children to make and use such common implements as are most in demand at home; and by allowing them the use of the school-tools to make family repairs. The system has proved very successful in Sweden, Norway, and Finland.

Protection of Building-Stone.—All methods of protecting building-stone against decay depend upon filling the pores of the stone with some substance that shall exclude water, the vehicle by which acids are introduced. This is easily done while the builders are handling the stone, but it is very hard after the structure has been set up to paint on the water-proof material so as to insure its absorption to any considerable depth. Several processes including the use of silicate solutions have been described by Mr. W. G. Dent as having been used with more or less of success. Oxalate of alumina applied to limestones gives them a coating of the insoluble double oxalate. Organic substances like linseed-oil give considerable protection for a time, but are ultimately oxidized. Among inorganic or mineral substances paraffine has been used, as upon the obelisk in Central Park, with a degree of success; but the objection holds against its application that the stone has to be warmed to secure a sufficient depth of absorption. The obelisk on the Thames Embankment, London, has been treated with a preparation of solution of gum-resins in petroleum spirit. But, Mr. Dent says, "if care be taken in the selection of the stone, it is only under special and exceptional circumstances that it will be considered desirable to resort to methods of preservation which must necessarily be expensive, and can only be regarded as the best cure for defects that admit of no other remedy."

The Wild Cattle of New Zealand.—The New Zealand farmers lost great numbers of cattle during the Maori wars which ended in 1868, through their being turned loose by the enemy and by other accidents incident to a season of disorder. These animals and their descendants now roam wild in the bush, particularly on the North Island, where they afford a sport "that is little less exciting and dangerous than that which exists in South Africa and the Western prairies of America." They are exceedingly difficult to reach, on account of the character of the bush around which they hover, which is composed of the long, twining creeper known as "supple-jack." No horse will try to penetrate this bush, because the instinct of the animal tell.? him that he will get his feet and legs entangled in the vines. "Not so, however, the wild cattle; they will, when surprised, rush madly into the densest shrubbery, and seem fully aware that nothing can possibly follow them into it; and it is thus that instinct has induced these cattle to bid defiance to man, and to live their primitive life over again."

Various Kinds of Soap.—According to a lecture by Dr. Stevenson Macadam, the remains of a well-organized soap-factory have been found in the ruins of Pompeii. Soap-factories existed in Italy and Spain in the eighth and in France in the ninth centuries. The manufacture in Great Britain is first heard of in the fourteenth century. White soap is generally prepared from tallow, with a little lard and palm-oil. In