HAVING been asked by a youngster in whom I am interested to build a toy bridge, it occurred to me to teach him the principles on which a railroad "truss-bridge" is constructed, so that the building of the toy would be an object-lesson in engineering.

The materials used were a cigar-box, some soft iron wire, and a piece of half-inch board. The cigar-box was cut up into half-inch strips, and a hole was burned with the wire near each end of each strip. The four inclined wooden "end posts" have holes eight and a half inches apart; the four vertical posts have holes five inches apart; and the two "upper chords" have holes seven inches apart. The six lower wires, or "bottom chords," have loops or "eyes" at seven inches' distance; the four "crossbraces" of wire on the sides have eyes eight and five eighth inches apart. The six floor

and upper beams are half an inch square and four inches long. The flooring consists of three pieces of the half-inch board, which are four inches wide, seven inches long, and which are cut out on the ends (as may be seen in the illustration where one of the pieces of flooring lies on the table, lower side up) to fit the floor beams. The wires that form the top braces are easily fitted after the other parts are in place. Screws hold the bridge at the joints, and the parts are easily put together by noticing their relation in the picture. It will be seen that the parts of the bridge are all hinged together - that is, they are not rigidly fastened, but are free to turn on the screws which unite them. This makes it certain that each member shall be subjected only to a simple push or a simple pull, to either compression alone or tension alone; and for this reason the

wooden parts are called " compression members," while the wire parts are called "tension members." This arrangement, so that each part shall have no twisting or bending to resist, makes the strongest possible bridge out of a given amount of material.

All bridges of this class depend upon a property of the triangle: that it is impossible to change its shape without lengthening or shortening one of its sides. Of four-sided figures this is not true. On examining the sides of this bridge, it will be found that they are entirely made up of triangles fastened together by the screws, although the same wire or piece of wood sometimes belongs at the same time to

two triangles. These triangles depend upon and support one another, so that if one member of one triangle should break, the whole structure might fall.

In planning real bridges, it is found by calculation which of the members will be under compression, and which will have to stand tension; and they are made of wood, or of cast-iron columns, or of metal rods accordingly.

In a bridge constructed on these principles the material is used to the best advantage, so that a comparatively light structure possesses great strength. The little bridge from which the illustration was made sustained a weight of twenty-five pounds.

WHILE rambling one evening in the woods, I sat down on a rock close by a shaded bank all overgrown with soft green moss and feathery ferns. Not far away there was an ancient treestump, with a hole running in underneath it; and what should I see peeping out from the hole, but the head of a little reddish-brown animal. At first sight I took it to be a chipmunk. Its large black eyes seemed full of apprehension, and as I moved it drew back out of sight.

On rolling over the stump, I discovered beneath it some withered grass carefully rolled into a globular nest. Cautiously drawing my handkerchief around this, I tied it up, with whatever it contained, and hurried homeward with my treasure. On emptying the handkerchief into a box covered with wire gauze, I found that I had captured two beautifully delicate and elegant creatures, somewhat larger than mice. Their fur was thick and soft, a rich velvet of reddish-brown on the back, and snowy white beneath. Their feet also were white. But their chief beauty lay in their eyes great, black, liquid orbs half protruding from the head. No gazelle ever had eyes half so lovely.

They soon became quite tame, and without showing any fear would allow me to put my hand into their cage to give them fruits and berries. They carried their nest into a corner of the cage and reconstructed it there.

Some

After about two weeks I procured a large cocoanut, sawed it in two, and taking one half of it, made in it a little doorway. When I put this into their cage, turned mouth down, they seemed to go wild with the excitement of delight. In and out they ran through the little doorway a hundred times in succession. times they would jump up on top of the cocoanut and survey it all over; and then, after "washing their faces " with their delicate white paws, jump down, and again run inside. Soon they made up their minds to take possession of it as their home. Their nest in the corner they pulled to pieces, and carried it off mouthful by mouthful into the little cocoanut hut. There they have lived ever since.

During the daytime they sleep; but when evening comes on they busy themselves running and jumping about the cage; and they have never once in three years tried to gnaw their way out.

They take nuts from my fingers now; and it is ridiculously amusing to see one of them running off with a large walnut, almost as big as himself, rolling and pushing it with his little paws, striving to force it in through the door in the cocoanut; and when the mouse finds that he cannot push it in from the outside, he himself gets inside, and putting out his head, tries to pull the nut in after him with his teeth. Their favorite food is nuts, which of course they cannot crack, and yet they get at the inside very cleverly; for with their sharp chisel-teeth they dexterously gnaw a hole through the hard shell, and then scoop out the meat from the interior. In a hazelnut they make only one hole; but they know that there is a division in a hickory-nut, so in that they make two holes, one on each side. They understand too, somehow or other, that in a walnut there are several divisions, so for each of the compartments they make a separate opening. A bad nut they will very seldom take the trouble to look into. How they divine that it is bad is a mystery, but they can nearly always tell.

They are fond of nice pears and apples, and one such fruit will last them both for a week. They get no water; the pear or apple does for drink.

It is a pretty sight to see one of them sitting up on its haunches on top of a large rosy apple, holding a filbert between its fore paws, while with its long lower teeth it greedily scoops out the savory kernel. Sometimes the other one will come over to take away the filbert from the one that has opened it, and then they have a contention, and they frequently chase one another around the cage, while the coveted filbert many times changes owners.

coming down whenever they feel thirsty, to take a bite at the juicy apple.

Every year, when October comes around, they make themselves wondrously busy, carrying all the nuts they can find into their cocoanut dwelling. When that is filled they pile them around the door, and store others in the corner of the cage. But no matter how many they may have, they will always eagerly take more.

In summer they spend very little time in their cocoanut, preferring to sleep outside in the coolness, generally perching high up on a branch placed in the cage for the purpose. They run up this branch as nimbly as squirrels, and usually squat there all through the heat of the day, close together on one of the thicker twigs,

A FAMILY OF DEER-MICE.

from my fingers when I offer them, and will add them to the store.

A few times, while I was brushing out their cage, they have jumped out into the room and hidden themselves away among my books; but invariably when I go and sit quiet in my chair. they go back to their cage, with its snug cocoa

IT seemed to 66 Mop's" master, after the passing away of Mop, that the master's earthly account with dogs was closed.

The pain of parting was too great to be endured. But another Dandy came to him, one Christmas morning, to fill the aching void; and for a time again his life is not a dogless one. The present ruler of the household has a

ANOTHER DANDY.

pedigree much longer and straighter than his own front legs. Although he comes from a distinguished line of prize-winning thoroughbreds, he never will be permitted to compete for a medal on his own behalf. The Dog Show should be suppressed by the Society for the Prevention of Cruelty to Dogs. It has ruined the dispositions and broken the hearts

of very many of the best friends humanity ever had.

Mop's successor answers to the name of Roy

when he answers to anything at all. He is young, very wilful, and a little hard of hearing, of which latter affliction he makes the most. He always understands when he is invited to go out. He is stone-deaf, invariably, when he

is told to come back. But he is full of affection, and he has a keen sense of humor. In the face he looks like Thomas Carlyle, and Professor John Weir declares that his body is all out of drawing!

At times, his devotion to his mistress is beautiful and touching. It is another case of "Mary and the Lamb," you know. If his mistress is not visible, he waits patiently about, and he is sure to go wherever she goes. It makes the children of the neighborhood laugh and play. But it is severe upon the master, who does most of the training, while the mistress gets most of the devotion. That is the way with lambs, and with dogs, and with some folks!

Roy is quite as much of a fighter as was any one of the

three other dogs; but he is a little more particular in his likes and his dislikes. He fights all the dogs in Tannersville; he fights the Drislers' Gyp almost every time he meets him; he fights the Beckwiths' Blennie only when either one of them trespasses on the domestic porch of the other (Blennie, who is very pretty, looks like old portraits of Mrs. Brown