The Wonder Book Of Knowledge Part 42

Shortly after the first of the year, in 1916, the U. S. Consul at Sheffield, England, reported that a new steel had been introduced there for use in making table cutlery. It was said to be untarnishable and unstainable even when used with the strongest acid foods, as well as non-rusting. The new product, which is called "Tirth's Stainless" steel, can be thoroughly cleansed by ordinary washing with soap and water, and cutlery made from it will retain its original polish after use. The properties claimed for it are of the steel itself and not the result of any treatment; consequently knives made from the new product can easily be sharpened in the regular way without fear of resulting damage.

While the initial cost of cutlery made from "Tirth's Steel" will probably be about double the usual cost, for not only is the price of the steel considerably more than that of other steels used for the same purpose, but it also costs more to work up, it is nevertheless expected to prove a welcome discovery to restaurant and hotel keepers as well as other large users of table cutlery because of the immense saving in labor occasioned by its use.

Why is it Necessary to Keep Unusually Quiet when Fishing?

The experienced fisherman who smiles at the amateur's restless fidgeting and complaining has discovered by careful observation that the fish who swims around in such an exasperating manner just a foot or so away from the temptingly baited hook has had an advance tip that something out of the ordinary is going on up above him. For sound, whether it be the noise of an oarlock or a companion's casual remark, can be heard more than four times as easily by the fish in the water beneath than it can up above in the air. Sound travels very quickly through the air, traversing ten hundred and ninety feet in a second, but it reaches forty-seven hundred feet away under water in the same time.

When the crowd on the other side of the baseball grounds yells across the field it seems as though we have heard their cheers as soon as they have been given, and so we have for all practical purposes, although in reality half a second has elapsed while the sound has been coming across the field. The time taken by sound in traveling is more apparent when the volume is sufficient to carry it a long distance. The sound of an explosion of a large quant.i.ty of dynamite and ammunition in Jersey City was not heard in Philadelphia, ninety miles away, for over seven minutes after it occurred.

[Ill.u.s.tration: CLIFF DWELLINGS, WALPI, ARIZONA]

[Ill.u.s.tration: _Photo by Brown Bros._

HOMES OF THE LONG-AGO

Famous reproduction of the Cliff-dwellers' Ruins, near Colorado Springs, Col. The cliff-dwellers of early America built their habitations in the canyons of the Colorado and Rio Grande, where the action of the elements had worn away a layer of soft rock, leaving layers of hard rock above and below as roof and floor for the dwelling.]

What were the First Apartment Houses in this Country?

A great many years ago, long before the white men came to America, there was a race of Indians called "cliff-dwellers," because they built their dwelling places far up on the sides of steep cliffs. They probably made their homes so hard to reach in order that they might be safe from visits of their enemies. While many of their homes were small single-family houses, there were also a number of large two and three-story dwellings with many rooms in which different families lived.

Some of these cliff dwellings may still be seen in the valleys of the Rio Grande and the Rio Colorado and its tributaries. Close examination shows that many of them were very skilfully built, every advantage being taken of the natural rock formations, and the stones being dressed and laid in clay mortar, very much as the bricklayer does his work on an up-to-date apartment house today. The outsides of the buildings somewhat resembled the cement houses which have been put up in later days, a coat of clay being spread on the outside walls and carefully smoothed off.

Oftentimes the inner walls were plastered too.

Many relics of the inhabitants have been found in these cliff dwellings, although we cannot tell how they lived, for the region is now rainless and therefore dest.i.tute of food plants. Conditions must have been different then and the ground less barren.

Why do We Call 32 Above Zero "Freezing"?

We know that freezing is the transformation of a liquid into solid under the influence of cold. Each liquid always solidifies at some fixed temperature, which is called its freezing point, and the solid melts again at the same temperature. Thus the freezing point and the melting point, or point of fusion, are the same, and the point is always the same for the same substance.

Consequently the freezing point of water, or the melting point of ice (32 F.), is taken for one of the fixed points in thermometry. The freezing point of mercury is 39 below zero, of sulphuric ether 46 below zero, of alcohol 203 below zero F.

How is Fresco Painting Done?

In producing fresco paintings, a finished drawing on paper, called a cartoon, exactly the size of the intended picture, is first made, to serve as a model.

The artist then has a limited portion of the wall covered over with a fine sort of plaster, and upon this he traces from his cartoon the part of the design suited for the s.p.a.ce. As it is necessary to the success and permanency of his work that the colors should be applied while the plaster is yet damp, no more of the surface is plastered at one time than what the artist can finish in one day. A portion of the picture once commenced, needs to be completely finished before leaving it, as fresco does not admit of retouching after the plaster has become dry. On completing a day's work, any unpainted part of the plaster is removed, cutting it neatly along the outline of a figure or other definite form, so that the joining of the plaster for the next day's work may be concealed.

The art is very ancient, remains of it being found in India, Egypt, Mexico, etc. Examples of Roman frescoes are found in Pompeii and other places. After the beginning of the fifteenth century fresco painting became the favorite process of the greatest Italian masters, and many of their n.o.blest pictorial efforts are frescoes on the walls of palaces and churches.

Some ancient wall paintings are executed in what is called "Fresco Secco," which is distinguished from true fres...o...b.. being executed on dry plaster, which is moistened with lime water before the colors are applied.

Fresco painting has in recent years again been revived, and works of this kind have been executed in the British Houses of Parliament and other public and private buildings, more especially in Germany.

The Story of a Piece of Chewing Gum[26]

The original "chewing gum" was spruce gum, the exudation of the cut branches of the spruce or fir tree. Later, pure white paraffin wax, variously flavored, took its place, but only in its turn to give way to the "chicle" now almost exclusively employed.

Though its employment in the manufacture of chewing gum is of comparatively recent date, chicle was used by the Indians prior to the days of Columbus as a means of quenching their thirst. It was first commercially imported as a subst.i.tute for rubber, but its peculiar suitability for chewing gum has resulted in the entire product being consumed by that industry. In 1885 the United States imported 929,959 pounds of chicle. The growth of the chewing gum industry is shown by the importation of nearly 5,500,000 pounds for the year ending with June 30, 1910.

The trees are "tapped" during the rainy season. The sap, or juice, as it exudes has the appearance of milk, but gradually changes to a yellow color and is about the thickness of treacle. The tree drains rapidly, the full supply of "milk" being generally obtained within a few hours, but an interval of several years usually elapses before it will yield a fresh supply. The milk differs from the juice obtained from the sugar maple, for example, in that it is not the life sap of the tree, and the flow varies greatly, some trees which show full life yielding much less than apparently poorer specimens. "Crude chicle" is obtained by simple boiling and evaporation of the milk, accompanied by frequent kneading.

The product, as pressed in rough molds, is of a light gray color.

The bulk of the crude chicle manufactured is shipped in blocks to Canada, where it is further evaporated and carefully refined prior to importation into the United States. When the chicle arrives at one of the chewing-gum factories it is immediately turned over to the grinding department. It comes from Mexico in cakes, varying in size from twelve- to eighteen-inch cubes; these are a putty color, but in composition chicle is porous and brittle, particularly after it is thoroughly dried. In the cubical form it is said to contain from twenty-five to thirty per cent moisture. After it is ground and dried it is practically free of moisture, but one of the most difficult problems which the manufacturer faces is to thoroughly dry chicle before he proceeds to treat it for its introduction as the base of chewing gum.

The cubes are broken by a large steam hammer into irregular-shaped pieces weighing from a few ounces to a pound. These chunks are then run through grinding machines, which reduce the chicle to a coa.r.s.e meal.

Sometimes this breaking and grinding is done in Mexico, but the duty on ground dried chicle is five cents per pound more than upon cube chicle.

Chicle meal is dried upon frames in a special drying room, which is kept at a temperature of 80 F. An electric blower exhausts all of the moisture from the air. The pure meal is then transformed into a thick syrup under intense heat and pa.s.sed through a filtering machine, one of the latest and most expensive pieces of machinery employed in the entire manufacture of chewing gum. This machine has practically solved the perplexing problem of separating impurities and foreign substances from chicle. Before the filterer was invented it was almost impossible for the manufacturer of chewing gum to produce gum entirely free from particles of grit.

During the process of filtration the chicle is also sterilized, and comes from the machine as pure as distilled water.

[Ill.u.s.tration: A BATTERY OF SUGAR-COATING MACHINES]

[Ill.u.s.tration: A CORNER OF THE SCORING ROOM]

[Ill.u.s.tration: THE LABORATORY]

[Ill.u.s.tration: WRAPPING AND PACKING DEPARTMENT]

It is next pa.s.sed to the cooking department and placed in huge steam-jacketed kettles, which revolve continually and thus keep the chicle from scorching. While it is being cooked in these large kettles sugar is added, and as soon as the gum is done it is placed in a kneading machine. It is now about the consistency of bread or cake dough, and after being kneaded and cooled, flavor is added.

Peppermint, spearmint and other oils used are triply distilled and absolutely free of all impurities. The orange oil comes from Messina and is always the product of the very latest orange crop.

From the kneading machine it reaches a sizing table, to which are attached heavy rollers for reducing the ma.s.s of gum to a strip about a quarter of an inch in thickness and twelve inches wide.

At this stage it will be seen the gum begins to take on a ribbon shape.

As it comes from the first series of rollers, it is cut into short lengths sprinkled with powdered sugar, and these short lengths are pa.s.sed in sticks about two feet high on to a second series of rollers.

Under the second rollers each short length of gum is once more reduced in thickness and extended in length.

The surfaces of the second rollers contain knives running lengthwise and around. These knives partially cut the gum to its final size. The thin sheets are then sent to another drying room. They remain in this room from twelve to forty-eight hours, according to the season of the year, and are then ready for the wrapping machines.

Machines have also been invented which stamp out little nuggets of gum.

To be finished these pieces are sent to a long room containing a line of twelve large white kettles, each on a separate base. It is these machines which coat the nuggets with snowy sugar. The kettles revolve until a sufficient coating of the liquid sugar has adhered.

The chewing gum wrapping machine is considered by machinery builders to be one of the most ingenious automatic manufacturing machines in use. It is about the size of an ordinary typewriter desk and is operated by one girl. She receives the thin sheet of partially cut gum from the last drying room. The machine operator drops the slabs of gum into a feeding chute. Each slab is here automatically wrapped in wax and silver-foil papers. These papers are fed from rolls, as printing paper is fed to a newspaper press.

As the slabs are wrapped they slide into a pocket. When five of them are finished, two steel fingers remove them and put on the final outside wrapper. The complete, wrapped packages of five slabs slide along a little runway into boxes.

The same girl who feeds the gum into the wrapping machine closes the lids of the boxes and places them on a packing table by her side. When the packing table is filled with boxes a boy removes it to the shipping room, where it is crated and forwarded to the wholesale dealers.