Page:Popular Science Monthly Volume 40.djvu/884

862 when it reached the other side. Another flock of lambs, confined in a straw-yard, had steeple-chases over a row of feeding-troughs stuffed with hay, right down the yard and back again. On a Yorkshire moor they have been seen to race, for a quarter of an hour, round a spring, and back to the ewes. Fawns play a kind of cross-touch from one side to the other, the "touch" in each case being given by the nose. Little pigs are also great at combined play, which generally takes the form of races. Emulation seems to form part of their amusement, for their races seem always to have the winning of the first place for their object, and are quite different from those combined rushes for food or causeless stampedes in which little pigs are wont to indulge. Racing is an amusement natural to some animals, and, being soon learned by others, becomes one of their most exciting pastimes. Many horses, and all racing-dogs, soon learn to be as keen at winning as public-school boys in a half-mile handicap. It is a common impulse with horses to pass, or at least to keep up with, any other horse in their company, and this instinct, developed by training, makes the professional race-horse eager to win. Animal enthusiasm for racing is well—the writer in the Spectator says best—seen in a dog-race. Birds especially delight in the free and fanciful use of their wings. There is all the difference possible between the flight of birds for "business" and pleasure; and many kinds on fine days will soar to vast heights for pleasure alone. In any comparison of the games and sports of animals with our own enjoyment of the same amusements, it must not be forgotten that imagination, the make-believe which enters into so much of the best play of children, is also the basis of much of the play of young animals. Watch a kitten, while you tap your fingers on the other side of a curtain or table-cloth, imitating the movements of a mouse running up and down. She knows it is not a mouse. But she enters into the spirit of the game, and goes through all the movements proper to the chase. Or perhaps she has a ball. If you set it in motion, so much the better—that helps "the make-believe." The ball is "alive," and she catches it, claws it, and half kills it, taking care all the while to keep it moving herself. The beautiful young lion, given by the Sultan of Sokoto to Queen Victoria last year, would play in exactly the same way with a large wooden ball, growling and setting up the crest, and pursuing the ball across the cage.

Durability of Oil Paintings.—Much time has been devoted by Mr. A. P. Laurie to the study of the means of insuring the durability of oil paintings. Some of the paintings of the old masters are still remarkably brilliant in coloring. A Van Eyck in the National Gallery is especially mentioned in M. Laurie's paper before the Society of Arts as having its colors all fairly well preserved, and a green—one of the most difficult of colors—wonderfully so. The quality is found not to reside in the pigments used, which were not superior to those of the present. It must, therefore, lie in the vehicle. It has been shown by Prof. Russell and Captain Abney that most fugitive pigments are permanent if protected from moisture, and a still larger number if protected from both air and moisture. If, therefore, we can obtain a vehicle which will really protect the particles of the pigment from moisture, we may use safely many pigments that are now regarded as fugitive. Mr. Laurie tested the qualities of linseed and walnut oils, the resins, and mixtures of oil and resins. His experiments showed that linseed oil, no matter how carefully refined, or in what way it is converted into boiled oil, can not be depended upon to protect a surface from moisture. Walnut oil proved no better. Solutions of resins in spirits of turpentine or benzol give as varnishes sufficient preservation from moisture for all practical purposes, but, forming a brittle and not very durable surface, are not fit to be used as mediums in place of oils. Eastlake's theory that the Flemish painters secured permanency by grinding their colors in oil and adding a little varnish, was tested and found not correct. No preparations of that kind experimented upon resisted the attacks of moisture; but a good mastic varnish was more efficient, and proved superior to any other substance tried. The use of copal or amber dissolved in spirit is also objectionable, because the varnish is difficult to remove. By using mastic, we have a varnish