The study of the natural sciences is a never-failing source of delightful occupation, and has a direct and positive tendency to create and keep alive both religious and moral sentiment. No one who opens, in a proper spirit, the great book of nature, can ever fail to turn from its contemplation with a more devout and reverential acknowledgment of the Divine Author's infinite wisdom, goodness, and power. INSECTS.—The number of distinct species of insects already known and described cannot be estimated at less than two hundred thousand—there being nearly twenty thousand different beetles alone, known at the present time—and every day is adding to the catalogue. CLOTHING OP THE EARTH.—The globe is a mass of vegetable life. Plants are the universal covering—the dress of the naked earth. They perform vast functions, reclaiming, extending, and improving it. They are the basis of animal life and existence ; their very beauty, their social and benevolent language, render even this troubled scene a place of delight. He who communes and meditates among trees and flowers shall find his Maker there to teach his listening heart. CELLS OP BEES.—The shape which bees give to their cell is a regular hexagon. They could not have chosen a figure which would have afforded them a greater number of cells in the space contained in the hive. The property of this figure is that many united together completely fill up a space round a certain point, without leaving any void whatever. AIR BLADDERS.—Fish possess the power of rising or sinking, by means of an air bladder ; when distended with air, the fish is buoyed up, and remains on the surface of the water without any effort of its own. On compressing the bladder by the action of the surrounding muscles, the included air is condensed, and the fish sinks to the bottom. On relaxing the same muscles, the air recovers its former dimensions, and the fish is again rendered buoyant. PERUVIAN BARK.—This is the bark of a tree found in South America, which contains in it the powerful bitter and tonic quinia. The sulphate of quinine is obtained by treating the bark with sulphuric acid, when the compound crystallizes out. It is much used in medicine, in doses of from one to six grains, according to the age and condition of the patient. THE LABORATORY.—The four interesting articles which have recently appeared in the SCIENTIFIC AMERICAN upon this subject were prepared by Mr. Septimus Piesse—our esteemed London correspondent. He wields the pen of a ready writer upon any topic that stands related to the laboratory. His information is gathered out of a large experience in the preparation of all the choicest articles for the toilet. Among the most fragrant scents we have ever met with is the " Frangi-panni, an eternal perfume," prepared by Mr. Piesse. It can be obtained"of Inger & Co., Broadway, New York. THE AGE OF OYSTEKS.—The process by which oysters make their shells is one of the most singular phenomena in natural science, and from the successive layers or plates overlapping each other, found on them, their age can be ascertained. Each layer makes a year's growth, so that by counting them, the year the bivalve came into the world can at once be determined. Up to the time of their maturity the layers are regular and successive, but after that time they are piled one over the other, and give a more thick and bulky appearance to the oyster. A composition made of roasted starch, salts of soda, and magnesia has been patented in England by F. G. Calvert and C. Lowe, as a substitute for glue and other animal size employed in dressing textile fabrics. The illuminating power of the electric light is to the best wax candle, as 1444 is to 1.