(3) A second thread is passed between the thread and the needle (by means of a shuttle or its equivalent) when the needle is at its lowest position.
(4) The needle returns while a take-up retracts the thread so as to tighten the stitch.
“This cycle would, for hand work, be immeasurably more complicated and difficult than ordinary sewing, but it consists of operations mechanically easy of performance in swift and accurately timed sequence, and as the whole of the thread in use has no longer to be passed from one side of the fabric to the other as each stitch is made, it has brought with it the all-important advantage of our being able to work with a continuous thread. Here, then, is a magnificent example of ‘coding.’ It is not to be wondered at that the machines which it has given to the world are in well-nigh universal use, and have profoundly modified both our social and industrial economy.”
Obed Hussey and His Mower.
One of the supreme inventions of all time is the mower of Obed Hussey, of Maryland, devised in 1833, and afterward adapted to reaping. In the primitive reaping of tall grain one hand keeps the stalks upright, while the other hand cuts these stalks with a scythe. Hussey, in a masterpiece of “coding,” arrayed metal fingers which keep the grain from bending, while vibrating knives sever the stalks. To this day his invention remains the core of millions of mowers as well as reapers; it has economized labor to an extent beyond estimate, and by shortening the time required in harvesting has saved many million bushels of grain which otherwise would have been destroyed by bad weather.
Obed Hussey’s mower or reaper.
Not a few inventors of the first mark are found among the men of great ability who unite training in two distinct fields of science, whose alliances they thoughtfully cultivate.
New Modes of Attack.
Thus Helmholtz, at once a physician and a physicist, devised the ophthalmoscope, that simple instrument for observing the interior of the eye. On a plane less lofty an inventor’s success may turn on his width of outlook, his intimacy with fields remote from the home acre, so that he may gainfully ally two arts or processes that, to a casual glance, seem utterly unrelated or unrelatable. When a pneumatic tube between a post-office and a railroad station is obstructed, there would seem to be no promise of aid in a fire-arm. But snapping off its blank cartridge at the open end of the tube gives back an echo through the air within the tube; in measuring the interval between touching the trigger and hearing the echo, there is news as to where the tube is choked, the velocity of sound in air being known. From the labors of a postmaster let us turn to those of an apothecary, who pounds and grinds his drugs in a mortar which has descended from the day when it reduced grain to flour. The grindstones which succeeded the mortar were only in recent years ousted by Hungarian rollers of steel which separate the constituents of grain with a new perfection. Their excellence consists in imitating the crushing of the mortar, not in attempting the grinding of the familiar burrs.