Page images
PDF
EPUB

forests of Mexico. The question of domesticating these little creatures of course at once presents itself to the reader.

When it comes to a question of domesticating wild silk-spinning caterpillars, however, two difficulties arise. One of these is the problem of furnishing adequate quantities of the requisite food plant; the other relates to the taming of the insects. The silkworm is the domesticated insect par excellence. It has been kept in captivity for thousands of years, and, like the canary bird, has become incapable of taking care of itself. It shows no desire to escape from confinement, so long as it is supplied with food, and it has even lost the power of flight. If placed on a branch of a mulberry tree-its natural food plant-it is liable to fall off; and, if it tumbles, it is too helpless to walk up again.

silk

Consequently, worms are easy to keep. They are quite satisfied to stay in one spot, and they will feed on half-wilted leaves such as wild caterpillars would disdain to touch. In truth, they are so lacking in vigor that one important object in hunting for

sult, the silkworm of today builds a cocoon wholly disproportionate in size to the caterpillar that makes it or to the moth that issues from it. Other peculiarities, appearing accidentally, have been perpetuated by breeding, and at the present time there are nearly as many races

[graphic]

wild silk-making insects has been to induce the latter to breed with the silkworm moths, to render the silkworm stock more hardy. But, when the wild moth and the tame one are put together, the latter is usually killed by the former.

Utmost efforts have been made to improve the silk-making powers of the silkworm by the selection of breeding stock, and for thus purpose during thousands of years the largest cocoons have always been saved to produce moths. As a re

of the silkworm as of the dog, and that is a very large number.

The silkworm, it should be realized, is only one of many kinds of caterpillars that make silk. All caterpillars that make cocoons wrap them in silk. But not all caterpillars spin cocoons; and, of those which do, only some produce a desirable fiber in adequate quantity which can be reeled off. In this country we have two large species of moths which build goodsized cocoons wrapped with a reasonable

THE "SILKWORM OF THE SEA"-BIVALVE MOLLUSK AND A GLOVE WOVEN FROM THE SILKLIKE FIBER OF ITS ANCHOR ROPE.

moth is a Japanese species, which has been utilized to some extent for silkmaking in that country. Its caterpillar feeds on the oak tree, so that it can be bred in latitudes further north than are practicable for the silkworm, which depends upon the mulberry. Not long ago our Department of Agriculture obtained from Japan a small consignment of the eggs of this moth, for experimental purposes, but they failed to hatch. The cocoon built by the insect is of a beautiful greenish color, and is wound with a very fine quality of silk-as good, indeed, as that of the silkworm.

The color of the silk spun by caterpillars appears to depend upon the pigments which happen to be contained in the leaves on which they feed. Hence, doubtless, the green hue of the Japanese moth's cocoons. Silkworm cocoons are sometimes white, sometimes yellow, and occasionally green. As a result of recent experiments, made at Rubaix in France, it has been ascertained that the color of the silk produced by silkworms may be modified at will by staining with dyes the mulberry leaves on which they are fed. When the leaves were stained blue, the worms spun blue silk; when the Not distantly related to the Cecropia leaves were dyed red, the caterpillars

[graphic]

quantity of excellent silk. One of these is the Cecropia moth, and the other is the Luna moth. Attempts have been made to utilize their caterpillars as silkspinners, but not with success as yetpartly owing to the wildness of the in

sects.

[graphic][graphic][graphic][subsumed]

produced red silk; green, green silk, and

so on.

[graphic]

In South Africa a species of silk-making caterpillar is utilized in a way quite extraordinary. Its cocoons are gathered after the moths have emerged from them, and are thereupon attached by sewing to strips of leather which are made to serve as anklets, being tied about the lower leg. Into each empty cocoon is put a small pebble, so that, when the wearer of such anklets walks along, an agreeable rattling noise is produced.

Spiders produce a very beautiful silk, which would be available for commercial use if only enough of it could be obtained. Fabrics, in fact, have actually been made out of it. But, unfortunately, attempts to keep these arachnoids in confinement for the purpose of persuading them to spin have been uniformly unsuccessful, owing to their inclination to eat each other up. As a result of an experiment, there would usually be a small quantity of silk obtained, together with one large fat spider to represent the original industrial colony.

Even among the mollusks, it may be said in conclusion, there is one species that produces an exquisite silk. The animal, which is a bivalve, reasonably plentiful in the Mediterranean, attaches itself to rocks, or other solid objects on the bottom, by means of a sort of rope, or "byssus." The rope, which is extremely

HOW THE ANKLETS ARE WORN.

strong, may easily be divided into a multitude of glossy, silk-like threads, suitable for weaving. Gloves and other articles have been made out of this marine silk, for sale as curiosities.

Take Time to Sorrow

He that lacks time to mourn, lacks time to mend.
Eternity mourns that. 'T is an ill cure
For life's worst ills, to have no time to feel them.
Where sorrow's held intrusive and turned out,
There wisdom will not enter, nor true power,
Nor aught that dignifies humanity.

-SIR HENRY TAYLOR,

THE CARS PASSING OVER THE PITS, EASILY UNLOAD THEIR BURDEN.

[graphic][subsumed][merged small]

C

By H. M. Post

ONTINUED uncertainty of the coal supply, due to strikes, shortages and various other conditions beyond the control of manufacturers, has led the Western Electric Company, which is one of the largest electrical manufacturing concerns in the world, carefully to consider the problem of coal storage. In their plant, located at Hawthorne, Illinois, which has been built during the last few years, they decided, after having their engineers investigate every known system, to adopt that used by the British admiralty.

Two huge storage bins, constructed entirely of cement and concrete, one of 4,000 and the other of 10,000 tons capacity, hold this enormous supply of coal in safe storage, ready for use at all times. These bins are located below the normal ground level, and are constructed with tracks extending over them, so that they may be easily filled or emptied from the

cars.

[merged small][merged small][merged small][graphic]
[blocks in formation]
« PreviousContinue »