Read Ebook: Scientific American Supplement No. 344 August 5 1882 by Various

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I have seventeen cocoons of this hybrid species, which number may be sufficient for its reproduction. But the question arises, "Will the moths obtained from these cocoons be susceptible of reproduction?"

I extract the following passage from his article: "I was under the impression that hermaphroditism was the usual character of these hybrids; and it has suggested itself to my mind as a possibility, which I have not, at present, sufficient data either to prove or to disprove, that the sterility of hybrids in general may perhaps be partly due to hybridism having a tendency to produce hermaphroditism."

I had about eighty cocoons of another and larger race of Atlas imported from the Province of Kumaon, but only eight moths emerged at intervals from the 31st of July to the 30th of September. Not only did the moths emerge too late in the season, but there never was a chance of obtaining a pairing. In my report on Indian silkworms, published in the November number of the "Bulletin de la Societe d'Acclimatation," for the year 1881, compiled from the work of Mr. J. Geoghegan, I reproduce the first appendix of Captain Thomas Hutton to Mr. Geoghegan's work, in which are given the names of all the Indian silkworms known by him up to the year 1871.

I will now quote from letters received from one of my correspondents in Ceylon, a gentleman of great experience and knowledge in sericulture.

"I do not agree with the opinion expressed in one of your reports, that the short duration of the larva stage, caused by a high temperature, has the effect of diminishing the size of the cocoons, because the Atlas and Tusser cocoons produced at the sea-level here are quite as large as those found in the Central Provinces at elevations of three thousand feet or more. According to the treatise on the "Silk Manufacture," in "Lardner's Cyclopedia," the Chinese are of opinion that one drachm of mulberry silkworms' eggs will produce 25 ounces of silk if the caterpillars attain maturity within twenty-five days; 20 ounces if the commencement of the cocoons be delayed until the twenty-eighth day; and only 10 ounces if it be delayed until between the thirtieth and fortieth day. If this is correct, a short-lived larva stage must, instead of causing small cocoons, produce just the contrary effect."

These Kumaon Cynthia cocoons were somewhat smaller and much darker in color than those of the acclimatized Cynthia reared on the ailantus. The moths of this wild Indian Cynthia were also of a richer color than those of the cultivated species in Europe.

During the summer 1881, I saw cocoons of my own Cynthia race obtained from worms which had been reared on the laburnum tree. These cocoons were, as far as I can remember, of a yellowish or saffron color; which I had never seen before. This difference in the color of the cocoon was very likely produced by the change of food, although it has been stated, and I think it may be quite correct, that with many species of native lepidoptera the change of food-plants does not produce any difference of color in the insects obtained. With respect to the Cynthia worms reared on the laburnum instead of the ailantus, it may be that the moths, which will emerge from the yellow cocoons, will be similar to those obtained from cocoons spun by worms bred on the ailantus, and that the only difference will be in the color of the cocoons.

The Kumaon Cynthia cocoons, as I found it to be the case with Indian species introduced for the first time into Europe, did not produce moths at the same time, nor as regularly as the acclimatized species. The moths emerged as follows: One female on the 22d of July; one female on the 25th; one male on the 3d August; one female on the 19th; one male on the 28th of August; one male on the 2d September; one female on the 3d. A pairing was obtained with the latter two. Two males emerged on the 4th of September; one male on the 6th; one male and one female on the 22d; one female on the 23d; and one female on the 25th of September. Five cocoons, which did not produce any moths, contain pupae, which are still in perfect condition; and the moths will no doubt emerge next summer . As seen in my note, a pairing of this wild Indian Cynthia took place; this was from the evening of the 4th to the 5th of September. The eggs laid by the female moth were deposited in a most curious way, in smaller or larger quantities, but all forming perfect triangles. These eggs I gave to a florist who has been very successful in the rearing of silk-producing and other larvae; telling him to rear the Cynthia on lilacs grown in pots and placed in a hot-house, which was done. The worms, which hatched in a few days, as they were placed in a hot-house, thrived wonderfully well, and I might say they thrived too well, as they grew so fast and became so voracious that the growth of the lilac trees could not keep pace with the growth of the worms. These, at the fourth stage, became so large that the foliage was entirely devoured, and, of course, the consequence was that all the worms were starved. I only heard of the result of that experiment long after the death of the larvae; otherwise I should have suggested the use of another plant after the destruction of the foliage of the lilacs; the privet might have been tried, and success obtained with it.

Leaving these, I now come to the North American species.

The cocoons of Polyphemus I had in 1881 were smaller and inferior in quality to those I had before. Those received in 1878 and 1879 were considerably finer and larger than those which were sent in 1880 and 1881; besides, they were sent in much larger quantities. The cocoons received this year are finer than those of 1881, but yet they cannot be compared with those of 1878 and 1879.

The larvae of Polyphemus can be bred in the open air in England, almost as easily as those of Pernyi, and even Cynthia; they will pass through their five stages and spin their cocoons on the trees, unless the weather should be unexceptionally cold and wet, as was the case during the month of August, 1881, when the larvae had reached their full size; they were reared this year on the nut-tree, and some on the oak. The species is extremely polyphagous, and will feed well on oak, birch, chestnut, beech, willow, nut, etc.

The moth of Polyphemus is very beautiful, and, as in some other species, varies in its shades of color. The larva is of a transparent green, of extreme beauty; the head is light brown; without any black dots, as in Pernyi; the spines are pink, and at the base of each of them there is a brilliant metallic spot. When the sun shines on them the larvae seem to be covered with diamonds. These metallic spots at the base of the spines are also seen on Pernyi, Yama mai, Mylitta, and other species of the genus Antheraea, all having a closed cocoon, but none of these have so many as Polyphemus.

The cocoons of the species of the genus Actias are closed, but the larvae have not the metallic spots of the species of the genus Antheraea.

Gloveri moths emerged from the 15th of May to the end of June; five pairings took place as follows: 1st, 4th, 9th, 24th, and 26th of June. First stage--larvae quite black. Second stage--larvae orange, with black spines. Third stage--dorsal spines, orange-red; spines on sides blue. Fourth stage--dorsal spines, orange or yellow, spines on the sides blue; body light blue on the back, and greenish yellow on the sides; head, green; legs, yellow. Fifth and sixth stage--larvae nearly the same; tubercles on the back yellow, the first four having a black ring at the base; side tubercles ivory-white, with a dark-blue base.

With twenty-four pupae of Imperialis I obtained nineteen moths from the 21st of June to the 19th of July; five pupae died. Two pairings took place; the first from the evening of the 13th to the morning of the 14th; the second from the evening of the 15th to the morning of the 16th of July.

The ova, which are about the size of those of Yama-mai, Pernyi, or Mylitta, are rather flat and concave on one side, of an amber-yellow color and transparent, like those of sphingidae. When the larvae have absorbed the yellow liquid in the egg, and are fully developed; they can be seen through the shell of the egg, which is white or colorless when the larva has come out.

The larvae of Imperialis, which have six stages, commenced to hatch on the 31st of July; the second stage commenced on the 7th of August; the third, on the 17th; the fourth, on the 29th of August; the fifth, on the 18th of September; and the sixth, on the 1st of October. The larvae commenced to pupate on 13th of October.

The larvae of this curious species vary considerably in color. Some are of a yellowish color, others are brown and tawny, others are black or nearly black. My correspondent in Georgia, who bred this species the same season as I did, in 1881, had some of the larvae that were green. In all the stages the larvae have five conspicuous spines or horns; two on the third segment, two on the fourth, and one on the last segment but one; this is taking the head as the first segment with regard to the first four spines These spines are rough and covered with sharp points all round, and their extremities are fork-like. In the first three stages they are horny; in the last three stages these spines are fleshy, and much shorter in proportion than they are in the first three stages. The color of the spines in the last three stages is coral-red, yellowish, or black. In the fifth and sixth stages the spine on the last segment but one is very short.

Here are a few and short notes from my book:

One larva on fourth stage was different from all others, and was described at the British Museum by Mr. W. F. Kirby as follows: "Larva reddish-brown, sparingly clothed with long slender white hairs, with four reddish stripes on the face, two rows of red spots on the back, spiracles surrounded with yellow, black and red rings; legs red, prolegs black, spotted with red. On segments three and four are four long coral-red fleshy-branched spines, two on each segment, below which, on each side, are two rudimentary ones just behind the head; in front of segment two are four similar rudimentary orange spines or tubercles; last segment black, strongly granulated and edges triangularly above and at the sides, with coral-red; several short rudimentary fleshy spines rising from the red portion; the last segment but one is reddish above, with a short red spine in the middle, and the one before it has a long coral-red spine in the middle similar to those of segments three and four, but shorter"

It is only when these tropical species shall have been already reared in Europe that the emergence of the moths will be regular; then they will be single-brooded in Northern or Central Europe, and some will very likely become double-brooded in Southern Europe. But when just imported the moths of these tropical species will always be uncertain and irregular in their emergence; hence the importance of having a sufficient number of cocoons so as to meet this difficulty, i.e., the loss of the moths that emerge prematurely or irregularly.

Before I conclude, I shall repeat what I already stated in a previous report, that the sending of live cocoons and pupae from India and other distant countries to Europe, can easily be done, so that they will arrive alive and in good condition, if care be taken that the boxes containing these live cocoons and pupae should not be left in the sun or near a fire , and that they should at once be put in a cool place or in the ice-room of the steamer. The cocoons and pupae should be sent from October to March or April, according to distance, and it is most important to write on the cases, "Living silkworm cocoons or pupae, the case to be placed in the ice room."

To continue these interesting and useful studies, I shall always be glad to buy any number of live cocoons, or exchange them for other species, if preferable.

ALFRED WAILLY.

MOSQUITO OIL.

A correspondent from Sheepshead Bay, a place celebrated for the size of its mosquitoes and the number of its amateur fishermen, recommends the following as a very good mixture for anointing the face and hands while fishing:

Oil of tar. 1 ounce. Olive oil. 1 ounce. Oil of pennyroyal. 1/2 ounce. Spirit of camphor. 1/2 ounce. Glycerine. 1/2 ounce. Carbolic acid. 2 drachms.

THE CATHEDRAL OF BURGOS.

Illuminated by the morning sun it appears, at a certain distance, as if the pyramids were floating in space; further on is seen the marvelous dome of the transept, crowned with eight towers of chiseled lace-work, over the center of the church.

Pubic worship was held in a portion of the edifice nine years after the work was begun; from that time onward for three hundred years, various additional portions were completed. On March 4, 1539, the great transept, built fifty years previous, fell down; but was soon restored. August 16, 1642, at 6 1/2 o'clock, P.M., a furious hurricane overthrew the eight little towers that form the exterior corner of the dome; but in two years they were replaced, namely July 19, 1644: the same night the great bells sounded an alarm of fire, the transept having in some way become ignited. The activity of the populace, however, prevented the loss of the edifice, which for a time was in great danger.

THE PANAMA CANAL.

HISTORICAL NOTES.

When Cortez, in the year 1530, made the observation that the two great oceans could be seen from the peaks of mountains, he, in those remote days, preoccupied himself with the question to cut through the Cordilleras.

Therefore, the idea of an interoceanic canal is by no means a modern one, as travelers and navigators observed that there was a great depression among the hills of the Isthmus of Panama. As Professor T.E. Nurse, of the U.S.N., says in his memoirs:

"This problem of interoceanic communication has been justly said to possess not only practical value, but historical grandeur. It clearly links itself back to the era of the conquest of Cortez, three and a half centuries." It is a problem which has been left for our modern era to solve, but nevertheless its history is thereby rendered still more interesting, having needed so many centuries to bring it to an issue.

Spain, which acquired through her Columbus a new empire, lying near, as it was supposed, to the riches of Asia, could not be indifferent, from the moment of her discoveries, to the means of crossing these lands to yet richer ones beyond.

India, from the days of Alexander and of the geographers, Mela, Strabo, and Ptolemy, was the land of promise, the home of the spices, the inexhaustible fountain of wealth. The old routes of commerce thither had been closed one by one to the Christians; the overland trade had fallen into the hands of the Arabs; and at the fall of Constantinople, 1453, the commerce of the Black Sea and of the Bosphorus, the last of the old routes to the East, finally failed the Christian world. Yet even beyond the fame of the East, which tradition had brought down from Greek and Roman, much more had the crusaders kindled for Asia and its riches an ardor not easily suppressed in men's minds.

The error of the Spanish Admiral in supposing that the eastern shores of Asia extended 240 degrees east of Spain, or to the meridian of the modern San Diego, in California--this error, insisted on in his dispatches and adopted and continued by his followers, still further animated the earlier Spanish sovereigns and the men whom they sent into the New World to reach Asia by a short and easy route.

Although these were grave blunders in geography and in navigation, the discoveries really made in the rich tropical zones, the acquirement of a new world, and the rich products continually reaching Europe from it, for a time aroused Spain from her lethargy. The world opened east and west. The new routes poured their spices, silks, and drugs through new channels into all the Teutonic countries. The strong purposes of having near access to the East were deepened and perpetuated doubly strong, by the certainties before men's eyes of what had been attained.

Balbao, in 1513, gained from a height on the Isthmus of Panama the first proof of its separation from Asia; and Magellan enters the South Sea at the southern extremity of the country, now first proven to be thus separate and a continent. Men in those days began to think that creation was doubled, and that such discovered lands must be separate from India, China, and Japan. And the very successes of the Portuguese under Vasco da Gama, bringing from their eastern course the expectancy of Asia's wealth, intensely excited the Spaniards to renew their western search.

The Portuguese, led around the Cape of Good Hope, had brought home vast treasures from the East, while the Spanish discoverers, as yet, had not reached the countries either of Montezuma or of the Inca. Their success "troubled the sleep of the Spaniards."

Everything, then, of personal ambition and national pride, the thirst for gold, the zeal of religious proselytism, and the cold calculations of state policy, now concurred in the disposition to sacrifice what Spain already had of most value on the American shores in order to seize upon a greater good, the Indies, still supposed to be near at hand. And since it was now certain that the new lands were not themselves Asia, the next aim was to find the secret of the narrow passage across them which must lead thither. The very configuration of the isthmus strengthened the belief in the existence of such a passage by the number of its openings, which seemed to invite entrance in the expectancy that some one of them must extend across the narrow breadth of land.

For this the Spanish government, in 1514, gave secret orders to D'Avilla, Governor of Castila del Oro, and to Juan de Solis, the navigator, to determine whether Castila del Oro were an island, and to send to Cuba a chart of the coast, if any strait were possible. For this, De Solis visited Nicaragua and Honduras; and later, led far to the south, perished in the La Plata. For this, Magellan entered the straits, which, strangely enough, he affirmed before setting out, that he "would enter," since he "had seen them marked out on the geographer Martin Behaim's globe." For this, Cortez sent out his expeditions on both coasts, exposing his own life and treasure, and sending home to the emperor, in his second relation, a map of the entire Gulf of Mexico . For this great purpose, and in full expectancy of success in it, the whole coast of the New World on each side, from Newfoundland on the northeast, curving westward on the south, around the whole sweep of the Gulf of Mexico, thence to Magellan's Straits, and thence through them up the Pacific to the Straits of Behring, was searched and researched with diligence. "Men could not get accustomed," says Humboldt, "to the idea that the continent extended uninterruptedly both so far north and south." Hence all these large, numerous, and persevering expeditions by the European powers.

Among them, by priority of right and by her energy, was Spain. The great emperor was urgent on the conqueror of Mexico, and on all in subordinate positions in New Spain, to solve the secret of the strait. All Spain was awakened to it. "How majestic and fair was she," says Chevalier, "in the sixteenth century; what daring, what heroism and perseverance! Never had the world seen such energy, activity, or good fortune. Hers was a will that regarded no obstacles. Neither rivers, deserts, nor mountains far higher than those in Europe, arrested her people. They built grand cities, they drew their fleets, as in a twinkling of the eye, from the very forests. A handful of men conquered empires. They seemed a race of giants or demi-gods. One would have supposed that all the work necessary to bind together climates and oceans would have been done at the word of the Spaniards as by enchantment, and since nature had not left a passage through the center of America, no matter, so much the better for the glory of the human race; they would make it up by artificial communication. What, indeed, was that for men like them? It were done at a word. Nothing else was left for them to conquer, and the world was becoming too small for them."

Certainly, had Spain remained what she then was, what had been in vain sought from nature would have been supplied by man. A canal or several canals would have been built to take the place of the long-desired strait. Her men of science urged it. In 1551, Gomara, the author of the "History of the Indies," proposed the union of the oceans by three of the very same lines toward which, to this hour, the eye turns with hope.

"It is true," said Gomara, "that mountains obstruct these passes, but if there are mountains there are also hands; let but the resolve be made, there will be no want of means; the Indies, to which the passage will be made, will supply them. To a king of Spain, with the wealth of the Indies at his command, when the object to be obtained is the spice trade, what is possible is easy.

But the sacred fire suddenly burned itself out in Spain. The peninsula had for its ruler a prince who sought his glory in smothering free thought among his own people, and in wasting his immense resources in vain efforts to repress it also outside of his own dominions through all Europe. From that hour, Spain became benumbed and estranged from all the advances of science and art, by means of which other nations, and especially England, developed their true greatness.

Even after France had shown, by her canal of the south, that boats could ascend and pass the mountain crests, it does not appear that the Spanish government seriously wished to avail itself of a like means of establishing any communication between her sea of the Antilles and the South Sea. The mystery enveloping the deliberations of the council of the Indies has not always remained so profound that we could not know what was going on in that body. The Spanish government afterward opened up to Humboldt free access to its archives, and in these he found several memoirs on the possibility of a union between the two oceans; but he says that in no one of them did he find the main point, the height of the elevations on the isthmus, sufficiently cleared up, and he could not fail to remark that the memoirs were exclusively French or English. Spain herself gave it no thought. Since the glorious age of Balbao among the people, indeed, the project of a canal was in every one's thoughts. In the very wayside talks, in the inns of Spain, when a traveler from the New World chanced to pass, after making him tell of the wonders of Lima and Mexico, of the death of the Inca, Atahualpa, and the bloody defeat of the Aztecs, and after asking his opinion of El Dorado, the question was always about the two oceans, and what great things would happen if they could succeed in joining them.

During the whole of the seventeenth and eighteenth centuries, Spain had need of the best mode of conveyance for her treasures across the isthmus. Yet those from Peru came by the miserable route from Panama to the deadliest of climates. Porto Bello and her European wares for her colonies toiled up the Chagres river, while the roughest of communication farther north connected the Chimalapa and the Guasacoalcos in Mexico, and the trade there was limited sternly to but one port on each side. As late as Humboldt's visit, in 1802, when remarking upon the "unnatural modes of communication" by which, through painful delays, the immense treasures of the New World passed from Acapulco, Guayaquil, and Lima, to Spain, he says: "These will soon cease whenever an active government, willing to protect commerce, shall construct a good road from Panama to Porto Bello. The aristocratic nonchalance of Spain, and her fear to open to strangers the way to the countries explored for her own profit, only kept those countries closed." The court forbade, on pain of death, the use of plans at different times proposed. They wronged their own colonies by representing the coasts as dangerous and the rivers impassable. On the presentation of a memoir for improving the route through Tehuantepec, by citizens of Oaxaca, as late as 1775, an order was issued forbidding the subject to be mentioned. The memorialists were censured as intermeddlers, and the viceroy fell under the sovereign's displeasure for having seemed to favor the plans.

The great isthmus was, however, further explored by the Spanish government for its own purposes; the recesses were traversed, and the lines of communication which we know to-day were then noted.

In addition to the fact that comparatively little was explored north or south of that which early became the main highway, the Panama route, there is confirmation here of the truth that Spain concealed and even falsified much of her generally accurately made surveys. No stronger proof of this need be asked than that which Alcedo gives in connection with the proposal by Gogueneche, the Biscayan pilot, to open communication by the Atrato and the Napipi. "The Atrato," says the historian, "is navigable for many leagues, but the navigation of it is prohibited under pain of death, without the exception of any person whatever."

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