A collection of woods without a parallel in the world is now being prepared for exhibition by the Directors of the American Museum of Natural History. Scattered about the third floor of the Arsenal, in Central Park, lie 394 logs, some carefully wrapped in bagging, some inclosed in rough wooden cases, and others partially sawn longitudinally, horizontally, and diagonally. These logs represent all but 26 of the varieties of trees indigenous to this country, and nearly all have a greater or less economic or commercial value. The 26 varieties needed to complete the collection will arrive before winter sets in, a number of specimens being now on their way to this city from the groves of California. Mr. S. D. Dill and a number of assistants are engaged in preparing the specimens for exhibition. The logs as they reach the workroom are wrapped in bagging and inclosed in cases, this method being used so that the bark, with its growth of lichens and delicate exfoliations, shall not be injured while the logs are in process of transportation from various parts of the country to this city. The logs are each 6 feet in length, and each is the most perfect specimen of its class that could be found by the experts employed in making the collection.

With the specimens of the trees come to the museum also specimens of the foliage and the fruits and flowers of the tree. These come from all parts of the Union--from Alaska on the north to Texas on the south, from Maine on the east to California on the west--and there is not a State or Territory in the Union which has not a representative in this collection of logs. On arrival here the logs are green, and the first thing in the way of treatment after their arrival is to season them, a work requiring great care to prevent them from "checking," as it is technically called, or "season cracking," as the unscientific term the splitting of the wood in radiating lines during the seasoning process. As is well known, the sap-wood of a tree seasons much more quickly than does the heart of the wood. The prevention of this splitting is very necessary in preparing these specimens for exhibition, for when once the wood has split its value for dressing for exhibition is gone. A new plan to prevent this destruction of specimens is now being tried with some success under the direction of Prof. Bickmore, superintendent of the museum. Into the base of the log and alongside the heart a deep hole is bored with an auger.

As the wood seasons this hole permits of a pressure inward and so has in many instances doubtless saved valuable specimens. One of the finest in the collection, a specimen of the persimmon tree, some two feet in diameter, has been ruined by the seasoning process. On one side there is a huge crack, extending from the top to the bottom of the log, which looks as though some amateur woodman had attempted to split it with an ax and had made a poor job of it. The great shrinking of the sap-wood of the persimmon tree makes the wood of but trifling value commercially. It also has a discouraging effect upon collectors, as it is next to impossible to cure a specimen, so that all but this one characteristic of the wood can be shown to the public in a perfect form.

Before the logs become thoroughly seasoned, or their lines of growth at all obliterated, a diagram of each is made, showing in accordance with a regular scale the thickness of the bark, the sap-wood, and the heart. There is also in this diagram a scale showing the growth of the tree during each year of its life, these yearly growths being regularly marked about the heart of the tree by move or less regular concentric circles, the width of which grows smaller and smaller as the tree grows older. In this connection attention may be called to a specimen in the collection which is considered one of the most remarkable in the world. It is not a native wood, but an importation, and the tree from which this wonderful slab is cut is commonly known as the "Pride of India." The heart of this particular tree was on the port side, and between it and the bark there is very little sap-wood, not more than an inch. On the starbord side, so to speak, the sap-wood has grown out in an abnormal manner, and one of the lines indicative of a year's growth is one and seven-eighths inches in width, the widest growth, many experts who have seen the specimen say, that was ever recorded.

The diagrams referred to are to be kept for scientific uses, and the scheme of exhibition includes these diagrams as a part of the whole.

After a log has become seasoned it is carefully sawed through the center down about one-third of its length. A transverse cut is then made and the semi-cylindrical section thus severed from the log is removed. The upper end is then beveled. When a log is thus treated the inspector can see the lower two-thirds presenting exactly the same appearance it did when growing in the forest. The horizontal cut, through the sap-wood and to the center of the heart, shows the life lines of the tree, and carefully planed as are this portion, the perpendicular and the beveled sections, the grain of the wood can thus be plainly seen. That these may be made even more valuable to the architect and artisan, the right half of this planed surface will be carefully polished, and the left half left in the natural state. This portion of the scheme of treatment is entirely in the interests of architects and artisans, and it is expected by Prof. Bickmore that it will be the means of securing for some kinds of trees, essentially of American growth, and which have been virtually neglected, an important place in architecture and in ornamental wood-work, and so give a commercial value to woods that are now of comparatively little value.

Among the many curious specimens in the collection now being prepared for exhibition, one which will excite the greatest curiosity is a specimen of the honey locust, which was brought here from Missouri. The bark is covered with a growth of thorns from one to four inches in length, sharp as needles, and growing at irregular intervals. The specimen arrived here in perfect condition, but, in order that it might be transported without injury, it had to be suspended from the roof of a box car, and thus make its trip from Southern Missouri to this city without change. Another strange specimen in the novel collection is a portion of the Yucca tree, an abnormal growth of the lily family. The trunk, about 2 feet in diameter, is a spongy mass, not susceptible of treatment to which the other specimens are subjected. Its bark is an irregular stringy, knotted mass, with porcupine-quill-like leaves springing out in place of the limbs that grow from all well-regulated trees. One specimen of the yucca was sent to the museum two years ago, and though the roots and top of the tree were sawn off, shoots sprang out, and a number of the handsome flowers appeared.

The tree was supposed to be dead and thoroughly seasoned by this Fall, but now, when the workmen are ready to prepare it for exhibition, it has shown new life, new shoots have appeared, and two tufts of green now decorate the otherwise dry and withered log, and the yucca promises to bloom again before the winter is over. One of the most perfect specimens of the Douglass spruce ever seen is in the collection, and is a decided curiosity. It is a recent arrival from the Rocky Mountains. Its bark, two inches or more in thickness, is perforated with holes reaching to the-sap-wood. Many of these contain acorns, or the remains of acorns, which have been stored there by provident woodpeckers, who dug the holes in the bark and there stored their winter supply of food. The oldest specimen in the collection is a section of the Picea engelmanni, a species of spruce growing in the Rocky Mountains at a considerable elevation above the sea. The specimen is 24 inches in diameter, and the concentric circles show its age to be 410 years. The wood much resembles the black spruce, and is the most valuable of the Rocky Mountain growths. A specimen of the nut pine, whose nuts are used for food by the Indians, is only 15 inches in diameter, and yet its life lines show its age to be 369 years.

The largest specimen yet received is a section of the white ash, which is 46 inches in diameter and 182 years old. The next largest specimen is a section of the Platanus occidentalis, variously known in commerce as the sycamore, button-wood, or plane tree, which is 42 inches in diameter and only 171 years of age. Specimens of the redwood tree of California are now on their way to this city from the Yosemite Valley. One specimen, though a small one, measures 5 feet in diameter and shows the character of the wood. A specimen of the enormous growths of this tree was not secured because of the impossibility of transportation and the fact that there would be no room in the museum for the storage of such a specimen, for the diameter of the largest tree of the class is 45 feet and 8 inches, which represents a circumference of about 110 feet. Then, too, the Californians object to have the giant trees cut down for commercial, scientific, or any other purposes.

To accompany these specimens of the woods of America, Mr. Morris K. Jesup, who has paid all the expense incurred in the collection of specimens, is having prepared as an accompanying portion of the exhibition water color drawings representing the actual size, color, and appearance of the fruit, foliage, and flowers of the various trees. Their commercial products, as far as they can be obtained, will also be exhibited, as, for instance, in the case of the long-leaved pine, the tar, resin, and pitch, for which it is especially valued. Then, too, in an herbarium the fruits, leaves, and flowers are preserved as nearly as possible in their natural state. When the collection is ready for public view next spring it will be not only the largest, but the only complete one of its kind in the country. There is nothing like it in the world, as far as is known; certainly not in the royal museums of England, France, or Germany.

Aside from the value of the collection, in a scientific way, it is proposed to make it an adjunct to our educational system, which requires that teachers shall instruct pupils as to the materials used for food and clothing. The completeness of the exhibition will be of great assistance also to landscape gardeners, as it will enable them to lay out private and public parks so that the most striking effects of foliage may be secured. The beauty of these effects can best be seen in this country in our own Central Park, where there are more different varieties and more combinations for foliage effects than in any other area in the United States. To ascertain how these effects are obtained one now has to go to much trouble to learn the names of the trees. With this exhibition such information can be had merely by observation, for the botanical and common names of each specimen will be attached to it. It will also be of practical use in teaching the forester how to cultivate trees as he would other crops.

The rapid disappearance of many valuable forest trees, with the increase in demand and decrease in supply, will tend to make the collection valuable as a curiosity in the not far distant future as representing the extinct trees of the country.--N.Y. Times.