Page:Popular Science Monthly Volume 21.djvu/288

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278
THE POPULAR SCIENCE MONTHLY.

exceptional families. The system can not, therefore, be safely recommended for towns in which a large proportion of the people are always ignorant and careless. The tub, cask, or pail system, which is used even on a large scale in England, France, and Germany, "is undoubtedly the best method of removal, where towns have neither water supply nor sewerage." In this system, the refuse matter is allowed to fall into a tub or cask, which is removed, emptied, cleaned, and disinfected by the town authorities at least once a week. At Manchester, England, sifted ashes are added during use to the contents of the tub, as a deodorizer. This system is successfully employed at Manchester and Rochdale, England, at an expense of $95 per thousand persons, or ten cents per person per annum; and is recommended for villages which can have no general water-supply. The weakness of it is, that the removal, cleansing, and disinfecting of the tubs require constant care and expense, and may be neglected by careless, ignorant, or parsimonious village authorities—a weakness rather attributable to village authorities than to the system—but under no circumstances could the evils of such neglect be comparable with those of privy vaults. The system is, however, unavoidably inferior to that of sewerage, in that it does not provide for the removal of wastewater and slops. Mr. Gardiner expresses a decided preference for the "separate" system of sewerage, which is adapted to carry off slops alone, to the "combined" system, in which the attempt is made to carry off both slops and storm-water by means of one set of conduits. He regards the separate system as vastly cheaper than the combined, and as very much more wholesome, in that it does not supply the territory for the cultivation of the bacteria that find rich and extensive propagating grounds on the moist, unglazed walls of the large combined sewers. A conspicuous example of the successful application of the separate system is found at Memphis, Tennessee.

 

Origin of the Son's Light and Heat.—Dr. H. R. Rogers, of Dunkirk, New York, has come forward with a criticism of the existing theories of the origin of the light and heat of the sun from combustion, mechanical action, or shrinkage of the sun's mass, as insufficient and not adequately supported by the analogies of any facts with which we are acquainted, and has advanced a theory that they are the result of electrical action. The sun, he believes, is a cold body, like the earth, but so constituted and so situated relatively to the earth that a stream of electric currents is constantly passing between the sun and the earth. These currents reach their points of greatest intensity within our atmosphere, where all the manifestations of force which we assign to the sun's surface really take place. Dr. Rogers also believes that the phenomena of gravitation may be traced to the same origin.

 

The Germination and Vitality of Seeds.—Dr. Richard E. Kunze, has collected a number of facts respecting the germination and vitality of seeds, in an essay which was read by him before the Torrey Botanical Club last December. Some seeds, to grow, must be planted immediately on maturity. Familiar examples are those of the elm and maple, the oak, and most of our common nuts. The seeds of the larkspur (Delphinium formosum), of some gentians, and of Angelica, partake of this character. Spanish chestnuts and filberts, however, have been sent, enveloped in wax, to the Himalayas, and plants from them are now growing there. Seeds of the Victoria regia had to be transmitted from America to England in water before the first plant was raised that came to perfection. Bosse, a German horticulturist, says that, when seed is to be kept for any length of time, it should be left in its natural covering. Other means of protection are sometimes available to preserve perishable seeds. Acorns will keep, packed in the hard ground, for centuries, and many seeds may be safely kept or transported in honey. Some seeds, like those of the Cucurbitaceæ, the balsam, stock, and wall-flower, improve with age to a certain extent. Many seeds are capable of preserving their vitality for years under ordinary conditions of dry exposure. Experiments by M. Alphonse de Candolle indicated that woody species preserved the power of germinating longer than others, while biennials were at the opposite end of the scale,