Ŏm'I nous foreshadowing good or evil, usually evil. Por tent': a sign, especially of evil. Rhythm: measured beat; movement in musical time. Chōres: the regular light work of a household or farm. Herd's grass: a kind of grass much used for hay. Stan'chion: a bar for confining cattle in a stall. Hěl'mět: a defensive covering for the head. The helmet was often adorned with a crest- a plume of feathers or other decoration—to show the rank of the wearer. Quĕr'ü loŭs: expressing complaint. Hōar'y: white, usually with age. Spher'ule: a little sphere. Ge o mět'ric: according to geometry, the branch of mathematics which treats of solids, surfaces, lines, and angles. Pěl'li cle: thin film or skin. Chinese roof: a high, peaked roof. A loof': away; at a distance. Pi'ṣä: a city of Italy. Pisa's leaning miracle: the famous leaning tower of Pisa. Ball Bearings 1. My attention was first directed to the subject when my brother James, coming home one day after a long spin, complained loudly that some one had been tampering with his bicycle. Finding it harder work than usual, he had got off to look at the bearings, and found that several of the balls were missing. It struck me as wonderful that so much extra work-and so much bad temper - should depend on a few small balls, and I was interested enough to study the subject. 2. Of course it is a question of friction. What is that, you say? Well, the word really means "rubbing," but a scientific man using it means the resist ance which is met by any surface in moving over another surface. 3. If you try to draw a heavy box along the ground by means of a rope, you will find it very hard work because the bottom of the box is pressed down against the ground, and the roughness of both surfaces causes resistance to movement. 4. That tells why carts and carriages and railway engines have wheels. The wheels bear the weight of the load above them, and a comparatively slight force is sufficient to move them; and when they move the friction between the rolling wheels and the ground is much less than would be the friction if the cart, carriage, or engine were dragged stiffly along the ground. In other words, rolling friction is always very much less than sliding friction. 5. That explains the use of the skid in going down the hill. The carter stops by means of it the rolling of his wheel, and thus by increasing the friction he lessens the speed of his descent. 6. What about the bicycle, then? Well, you must have noticed that all wheeled vehicles have an axle or two, and that the axle passes through the round hole at the hub or center of the wheel. The place where the axle bears upon the hub of the wheel is called the bearing. 7. Now, in ordinary carriages the bearing is a plain bearing; that is, the axle remains still while the wheel revolves directly on it. The parts are made very smooth and are kept oiled, in order to lessen the friction. 8. But in order to lessen still more the friction in the bicycle, ball bearings are employed. Look at the accompanying section of a bicycle wheel bearing. A is the hub of the wheel, which revolves on the axle, B; but it does not run directly on it. At each end of the hub there is a concave surface, C, called a cup, and at each end of the axle a convex surface, D, called a cone. These are both ground perfectly smooth and true, and in the hollow between them is a ring of smooth steel balls encircling the axle. 9. Now you see what happens. When the wheel turns, the hub turns on the balls. These in their turn roll round in the same direction with the same speed, and thus the hub, instead of sliding stiffly round on the axle, is itself as it were going on wheels. 10. That this device very much reduces the friction you can easily prove for yourself. Try to push a heavy box along the floor; with all your straining you can hardly move it. 11. Now take a handful of marbles, put them in three lines on the ground, and let the box lie evenly upon them. You can now move it with a touch. It is just the same with a ball bearing, except that the balls there are shut up in a cup and cannot escape as the marbles can slip away from under the box, and that the hub rolls, while the box slides. 12. I had hitherto thought that bicycling was as hard work as walking; but, when I found how ingeniously the makers have reduced the friction and consequently the labor of riding, I made up my mind to do most of my walking on wheels. Tăm'per ing: meddling; trying little experiments with. Skid: an iron clog or hook fastened to a chain and placed under a wagon wheel to keep it from turning when going down a steep hill. Con'cave: hollow and rounded, said of the inside of a curved surface or line, in opposition to convex. Con'věx: rising into a rounded form; said of a curved surface or line when viewed from without, in opposition to concave. De vice': contrivance; plan. A little neglect may breed great mischief: for want of a nail the shoe was lost, and for want of a shoe the horse was lost, and for want of a horse the rider was lost. - FRANKLIN The Irish Widow's Message to her Son in America BY ELLEN FORRESTER 1. "Remember, Dennis, all I bade you say, Tell him we're well and happy, thank the Lord, But of our troubles since he went away, You'll mind, avick, and never say a word, Of cares and troubles, sure, we've all our share, The finest summer isn't always fair. 2. "Tell him the spotted heifer calved in May She died, poor thing! but that you needn't mind Nor how the constant rain destroyed the hay; But tell him God to us was always kind; 3. "Be sure you tell him how the neighbors came, 4. "They came with ready hands our toil to share, 'Twas then I missed him most, my own right hand! I felt, although kind hearts were round me there, |