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THE POPULAR SCIENCE MONTHLY. 



ncss when it readied the other side. Anoth- 

 er flocli 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 gen- 

 erally takes the form of races. Emulation 

 seems to form part of their amusement, for 

 their races seem always to have the win- 

 ning 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. Rac- 

 ing is an amusement natural to some ani- 

 mals, 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 com- 

 mon 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 v/in. 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 fiight of birds for " business " and pleas- 

 ure ; and many kinds on fine days will soar 

 to vast heights for pleasure alone. In any 

 comparison of the games and sports of ani- 

 mals 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 cur- 

 tain 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 mo- 

 tion, 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 set- 

 ting 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 du- 

 rability of oil paintings. Some of the paint- 

 ings 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 ve- 

 hicle. It has been shown by Prof. Russell 

 and Captain Abney that most fugitive pig- 

 ments are permanent if protected from moist- 

 ure, 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 wal- 

 nut 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 sufiicient preser- 

 vation from moisture for all practical pur- 

 poses, 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 perma- 

 nency 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 objection- 

 able, because the varnish is difficult to re- 

 move. By using mastic, we have a varnish 



