Page:Popular Science Monthly Volume 33.djvu/294

282 " quality; the same property of gelatinizing is possessed in fruits by pectine, which is, however, a distinct substance. The stimulating properties of tea and coffee are due to their peculiar alkaloids, theine and caffeine; their flavor, to aromatic substances which are extracted by the hot water from the leaf or berry. Wheat-flour is composed of starch with gluten, and more or less of mineral or inorganic substances. The finer and whiter flours are nearly pure starch, and are not so nutritious as the less attractive brown flours. The raising of dough is a true process of fermentation, precisely similar to that of the brewer or distiller, but the alcohol soon passes away. Sugar, when heated, melts, and is converted into an uncrystallized, pliant mass, known as barley-sugar, or sugar-candy. At a somewhat higher temperature it is decomposed, and a dark-brown substance, known as caramel, is formed. Granulated sugar is seldom adulterated. The term salt, in its technical sense, includes the fats, which are compounds of characteristic acids with glycerin as a base. Upon adding potash or soda, the acid combines with the alkali, forming soap, and the glycerin is set free. If soda is used, hard soap, if potash, soft soap, is formed.

Purification of Sewage by Infiltration.—Filtration of sewage is defined in the report of the Royal Commission on Metropolitan Sewage Discharge to be its concentration, at short intervals, on an area of specially chosen porous ground, as small as will absorb and cleanse it; not excluding vegetation-culture, but making the produce of secondary importance. On a suitable soil, such as a sandy loam with a small proportion of gritty gravel, specially prepared by surface leveling and deep under-drainage, one acre is said to be capable of purifying the sewage of one thousand people, manufacturers' refuse and storm and surface waters excluded. Mr. Bailey Denton, who has had ten years' experience in filtration, and has published a book about it, does not think it necessary, or even, in most cases, desirable, to precipitate the sludge before applying the sewage to the filtration-beds. He does not believe that under proper treatment sludge is capable of clogging the pores of the land or of injuring vegetation. He advises the laying out of the filtration-beds in ridges and furrows, the sewage only to flow into the furrows and not to be allowed to flood the ridges on which plants and vegetables are growing. As soon as the deposit of sludge on the sides of the furrows is sufficient to prevent infiltration in any great degree, the sewage should be withheld from the areas so affected. The sludge should then be allowed to dry partially in the furrows, and when in a fit condition be lifted and dug into the ridges. The slimy matter, which has appeared so considerable and which puddled the bottom of the furrows when wet, shrinks to a skin of very insignificant thickness when dry, and is readily broken up and mixed with the soil. The intermittency of the application of the sewage to the filter-beds is essential. Each bed should have eighteen hours' rest out of the twenty-four, to allow air to follow the pores of the land, and thereby renew the oxidizing properties of the soil. The assimilative power of growing plants is doubtless also a great aid in the purification of sewage. Intermittent filtration is probably, however, likely to have its most useful application in combination with surface or broad irrigation.

The Slavic Feast of St. Nicholas.—The feast of St. Nicholas takes the place, among some of the Slavic peoples, of our Christmas. The chief feature of the festival is the catechization of the children on the eve of the day, for which the good bishop is personated by a youth dressed in long white vestments, with a silk scarf, and furnished with miter and crosier. He is accompanied by two angels, also suitably dressed, and followed by a troop of devils, having blackened visages, horns, pigs' faces, and other ingeniously devised distortions, and all rattling chains. The visitations take place at the houses where the children are gathered in their evening parties. St. Nicholas enters with two angels, while the devils are left outside. He calls up the children one by one, and seriously examines them, with questions suited to their ages, and in their knowledge of prayers and hymns. Those who pass the questioning successfully are rewarded with presents of nuts and apples; those who fail have to stand aside. After