CHEMISTRY.
[1.] “De Saussure,” sō-sür, Horace Benedict. (1740-1799.) A Swiss naturalist who traveled extensively and made valuable contributions to science. Much of his time and attention were given to mountain researches. He constructed the best hygroscope, the instrument which indicates a change in the degree of moisture in the atmosphere. The cyanometer, an instrument for measuring the degrees of blueness in the sky, was also invented by him.
[2.] “Osmose.” The tendency of fluids, when placed in contact, to mix.
[3.] “Cotyledons.” The seed lobes which surround and nourish young plants. Endogenous plants, or inside growers, such as Indian corn, have only one cotyledon, while exogens, or plants that grow by making external additions, have two, as seen in the young pea.
[4.] “Hales,” Stephen. (1677-1761.) An English clergyman who gave much time to scientific study. He was the author of several works, among which was a book on the physiology of vegetables, entitled “Statical Essays,” which has been translated into several languages.
[5.] “Dean Trench,” Richard Chevenix. (1807-⸺.) A British clergyman. In 1856 he was made Dean of Westminster, and in 1864 Archbishop of Dublin. His publications are numerous, including poetical, theological, philological, and historical works.
[6.] “Venus fly-trap,” or dionæa. This curious plant is a native of the sandy bogs of North Carolina. It is a perennial plant, whose leaves grow from its roots. In the midst of them there grows a leafless stem, about six inches high, which terminates in a cluster of white flowers. The long, slender leaves bear at their extremities a second leaf, which has been compared to two eyelids joined at their bases; this leaf is fringed with stiff, bristly hairs, and on the upper surface there are three very delicate bristles on each side, so placed that a fly can not walk over the leaf without touching one of them. As soon as touched the two parts of the leaf instantly close over the victim and hold it in their embrace until death follows, and the insect is partly absorbed. The sensitiveness of the plant resides entirely in these bristles on the surface of the leaves. The juice from the glands attracts the insects, and the plant receives nourishment from their bodies, which are partly dissolved in a liquid which exudes from the leaves.
[7.] “Nepenthes,” or pitcher plants. A genus of plants whose leaves form receptacles for water. The plants are natives of the swamps in the East Indies and Australia. The linear-lanceolate leaves have at their extremities a long, spiral stem, at the end of which is attached an urn, or pitcher, of narrow cylindrical form, from six to twelve inches long, in the different species, which are of the same color as the leaves, in some varieties, in others spotted with red, and still others are of a blood red color. The pitcher is terminated by a lid which is sometimes closed. The pitcher is always partly filled with watery liquid. Honey is secreted around the mouth of the pitcher, and insects are found within it, which have been lured by the honey. These are supposed to contribute to the nourishment of the plant. For further description, see the article on “Borneo,” in the present number of The Chautauquan. There are some varieties of the pitcher plant found in the United States.
[8.] “Diatoms,” A species of microscopic plants belonging to the Algæ or sea weeds, growing in both salt and fresh water. For a long time they were thought to belong to the animal kingdom, and were classed among the animalcules, as they had the strange power of secreting from the water silicious shells. They grew in some places in such abundance as to form large beds of their shelly remains, the material of which is used for the polishing powders known under the name of tripoli. The species found now are exactly like the fossils. Ehrenberg says: “Species are to be found, in a living state, in situations where they have been propagated from times far anterior to the existence of man.” They may be obtained by allowing the water in which they grow to stand for a time, and then pouring off all but the slimy part at the bottom. The diatoms may often be seen to move a little in the water, from which it was supposed they belonged to the animal kingdom. Professor Bailey describes one very interesting species, as follows: “At one moment the needle-shaped frustules lie side by side, forming a rectangular plate; suddenly one of the frustules slides forward a little way, the next slides a little also, and so on through the whole number. These motions are constantly going on, and with such rapidity that the eye can scarcely follow them. The cause of the motion is wholly unknown, but it is probably mechanical and not vital.” One species in its growth takes on a fanlike appearance and is exceedingly beautiful. Fossil diatoms have been found in all the strata of rock formations. These with some of the minute creatures of the animal kingdom have left greater records of themselves than most of the higher forms of life. Extensive deposits of their silicious shells are found in various parts of the world. The city of Richmond, Va., stands on a layer of them which is eighteen feet in thickness.