Page:The American Cyclopædia (1879) Volume I.djvu/522

 490 ANEMONE register the integral or quantity of the wind can be calculated that has blown to each point of the compass during the periods of the obser- vations ; and thence the resultant, or average effect of all the winds. The instrument now in use in the United States office for weather reports is Eobinson's anemometer, which con- sists of four horizontal arms (see figure) radiat- ing from a central point, at which is a vertical axis of revolution. A hollow hemispherical cup is attached to each arm in such manner that when the wind is pressing upon the con- cave side of a cup on one arm, the cup on the opposite arm presents its convex side toward the wind. The wind exerts more pressure on the concave side than on the convex, and hence causes the arms to revolve. The rate of revolution per minute gives the velocity of the wind. Each instrument has to be tested by placing it upon a moving body on a calm day. In this way it is easily found what the number of revolutions is which the instrument will give for any velocity ; it is then placed upon a high building, and its axis attached to a re- cording apparatus similar to that described above. Biram's anemometer is an instrument for measuring and registering the quantities of air which circulate through the passages of mines. It was invented in consequence of the recommendation of a committee appointed by the British house of commons, that the use of such an instrument should be adopted as a precaution against the explosions in coal mines. It is a disk of a foot diameter, made to revolve when placed in a current of air, and furnished with registering wheels like those upon a gas meter. Any want of attention on the part of those having charge of supplying the required current of fresh air is thus readily detected. ANEMONE (Gr. ive^uof, wind, as many species grow in elevated windy places), a genus of plants of the family of ranunculacece, Jtissieu. The leaves of the stem are generally ternate, forming an involucre which is more or less dis- tant from the flower ; the calyx corolla-like, with from 5 to 15 colored petals, longer than the stamens; carpels numerous, ending in per- sistent styles. About 60 species are cultivated on account of their beauty, succeeding best in light loamy soils. They are propagated by di- vision, fcrffsets, and seeds ; the greenhouse species from cuttings in light loam under glass. The colors of t^e flowers predominate in the follow- ing order on* over the other : white, yellow, blue, reddish white, purple, red, striped, whit- ish, creamy violet. Their recommendations for a place in the garden are : a fine dense foliage Anemone Hortensis. of beautiful green color ; involucre green, and distant about from the flower ; stem straight, light; flowers globose, petals large, rounded, with an unguis (nail) of different color. The native countries of the species are, in order of prevalence, Europe, especially the south, North America, Siberia, the rest of Asia, South Amer- ica, South Africa. The most valued are : The A. Tiortensis and stellata, often flowering the second year, easily doubled by culture ; flower- ing from mid-April to the end of May. A. pavonina, of Europe ; root tuberous ; flowers purple ; attains a foot in height ; a variety is crimson with green centre. A. ranunculoideg, of Europe, about 6 inches high. A. apen- nina ; leaves biternate; many narrow, blue petals. A. narci*ifolia, of Switzerland ; 10 inches; umbellated purplish and yellow. A. vit{folia, of Nepaul, japonica, and elegans (also from Japan), recommend themselves by their strong and tall frame (1 to 3 feet), and by the beauty of their flowers. A. capensw or arborea ; stem woody, though but 7 inches high ; flowers reddish outside, white inside. A. pulsatilla, common in Europe; 10 inches high ; flowers large violet; foliage hairy. A. coronaria, of Asia Minor ; hard to be raised from seed in this country. A new genus has been separated from the anemone, under the name of hepatica, to which belongs the beautiful species common- ly called anemone that adorns our forests in early spring; leaves leathery, dark green on the upper side, liver-brown on the lower; flowers numerous, of all shades of white and bluish purple. Both are allied to the clematids, hellebores, acteeas, and crowfoots, with which they form the 41 genera of ranunculacece. The hepatica was employed of old in liver com- plaints, from the belief in its sympathy with