The first things you see in a watch factory are spinning wheels— little whirling tables no bigger than the head of mama's sewing machine. There are rows and rows of them, connected by belts with flying pulley wheels overhead, and operated by men and women. These machines are lathes. Lathes are used for shaping round things in metal as well as in wood and clay. Here the lathes cut teeth on little brass wheels and threads on the outside of screws and the inside of screw-holes.

First, the round blanks for wheels are cut from strips of sheet brass. A brass ribbon as wide as the wheel is fed into a machine. A steam hammer with a die on the end as round and sharp-edged as a cooky cutter, comes down and cuts out little brass "cookies" that look like very thin, bright, telephone slugs.

Watch wheels all have holes in the middle like some cookies, and teeth or scallops around the edges. The hole is drilled first, and a number of blanks are strung on a rod like flat beads on a string. Then the rod is clamped into a lathe. The operator slips a belt over the wheel—whir-r-r, how it hums ! A steel chisel cuts a row of teeth up and down in all the blanks at once. Click, the rod turns a little and another tooth is cut.

A screw-making lathe clips a tiny bit of brass wire from a coil, whirls it under a chisel to point one end, strikes a blow that flattens the other end into a head, and saws a slot across the head for the screwdriver. Then a fairy chisel cuts a thread-like spiral groove from near the head down to the tapering tip. When it is done it isn't much bigger than a little brown seed. Hundreds of them can be put into a pill box, or a one-ounce bottle.

In a watch factory are big fire-clay ovens, or kilns, as there are in potteries, for baking—what do you suppose? The white china dials. Some dials are gilded or plated with gold, but most of them are enamelled on copper plates with fine white porcelain from the pottery. The wet clay paste, or dough, is spread on the dial plate, baked in the oven, ground down smooth and glazed. When they come out of the oven they shine like frosted cakes. A pattern printed on a fine transfer paper is laid carefully on the dial and pasted smooth. Into the oven it goes again. The paper is burned up but the pattern is burned in. The dial of papa's watch and your pretty china breakfast cup are decorated in much the same way.

The most delicate parts of a watch are the springs—the mainspring and the hair-spring. They are tiny ribbons and hairs of blue steel, so flexible that they can be coiled up tight, but so strong they can pull the wheels along. They are made of steel wire, ironed or rolled out flat, tempered by heat and cold, "blued," and with rivet holes bored in the ends. In a watch you can see the main spring beat and throb like a little live heart.

Machines make all the parts of a watch more perfectly and hundreds of times faster than men could make them by hand. But no machine can put all the parts of a watch together. A skilled

watchmaker, with a magnifying glass screwed into one eye, has to pick up the one hundred and fifty separate parts, some with magnets, and fit them all together into a compart circle that will slip right into a tiny gold shell of a case. And he has to do all this so the little machine will keep perfect time. No spring must be too short or too long, no screw too tight, no wheel or tooth must rub another.

When your watch runs down you ask someone the time, or you set it by a public clock. In watch factories every watch is set and regulated by the fixed stars. The sun is not the best time-keeper. It goes fast or slow, or it seems to do so. But the earth turns around and around in the same space of time, day after day. As it turns, certain fixed stars, or very distant suns that appear as stars, come into view at the same instant each night. In a big watch factory an astronomer has a telescope set so that these stars seem to pass across the lens. Really, watches are set by the earth we live upon. The hour-hand of a perfectly-timed watch goes twice around the dial in exactly the same time that it takes our dear old earth to turn over once on its axis. The heart of the big earth and the heart of the little watch beat together.

Isn't that very wonderful? And don't you think Old Father Time ought to carry a little bunch of stars? See Clock, page 411.