Page:Popular Science Monthly Volume 43.djvu/149

Rh growers use coal-oil cans filled with kindling wood and coal and placed in the orchard at the rate of from eight to twenty-five per acre. Some provide themselves with two gallon iron kettles and use reduced petroleum. Ten dollars per acre will pay for the plant and the expense of one night's burning. Horticulturists in other citrus colonies are following in the track of Riverside and preparing for future "cold snaps."

Curious Fauna of La Plata.—A curious medley of animal life is described by Mr W. H. Hudson as existing in the pampas region of La Plata: A poisonous toad which kills horses; the wrestler frog, which suddenly pinches its enemy with its fore legs and then runs away; a large, venomous, man-chasing spider, which pursues men on foot and on horseback; dragon flies, a single individual of which will cause clouds of gnats, mosquitoes, and sand flies to disappear in an instant; and an opossum, fully adapted to life in trees, which yet lives in a desert destitute of trees, and when brought to a tree, which it may never have seen before, will clasp it and climb it with all the agility of its forest dwelling relatives of North America.

Manufacture of Fans.—The manufacture of fans is chiefly carried on now in France, Spain, China, Japan, and India. The fashions are established m France principally at Sainte-Geneviève, Audeville, Corbeil-Cerf, Le Déluge, Coudray, and the vicinity of Beauvais and Méru. At Sainte Geneviève they work in bone, mother-of-pearl, and ivory; at Le Petit-Fercourt, and Andecourt, in mother-of-pearl and horn; at Le Déluge and Corbeil-Cerf, pear tree, apple tree, and hornbeam wood; at Boirsière, in bone; and at Paris, in shell. The leaf of the fan is generally made and the fan mounted at Paris. Fans have been made in Spain only for some sixty or seventy years, notably at Madrid, Barcelona, Valencia, Malaga, and Cadiz. Most of the Chinese fans are made in Canton and E-moui, but the manufacture is generally diffused through the country, for the fan is a part of the national costume. Every Chinese of good social standing holds a fan during visits of ceremony, and the custom of writing on fans is spread throughout the empire. The principal centers of production in Japan are the cities of Osaka, Kioto, and Nagoya. In that country the fan is a part of the costume of both sexes, and is to be seen in the hand of the soldier as well as in that of the monk. When a gentleman gives alms to a beggar, he often puts the coin upon his fan; and salutes are made by waving the fan as they are in Europe by tipping the hat. There are also fan factories in some other countries. Lace fans are made at Brussels and De Grammont, in Belgium; fans of braided straw, at Fiesole and Vicenza in Italy; and fan-standards of braided grass and cloth embroidered with gold and silver, in Tunis and Morocco; but France holds the first place in the manufacture of luxurious, and China in that of cheap, fans.

Origin of "Hot Waves."—A theory is published by Prof. F. Hawn, of Leavenworth, Kan., that our southwest winds are tropical currents, which rise to great elevations in the upper atmosphere, and then flow north and reach the ground again in latitude 34°, bringing subtropical heat. As other results of his theory he concludes that the close atmospheric relations between the upper and lower currents attest their common origin; that the atmospheric temperature is incidentally if not perpetually higher in the upper than on the lower levels; that these relatively higher thermal conditions of the upper atmosphere control the lower atmosphere in the spring and summer, and incidentally in the winter; that the hot waves of the Northwest have their origin in a superheated upper atmosphere, and are condensed by gravitation in their descent to the surface, evolving heat in a ratio inverse to the humidity; and that the foehn winds (hot waves), with their resultant temperatures of more than 100° in the temperate seasons and from 65° to 73° in the winter, are not local west of the eighty-eighth meridian, but at intervals simultaneously cover the northern half of the United States.

Qualities of Slates.—From experimental studies with roofing slates, Mr. Mansfield Merriman has drawn the conclusions that those with soft ribbons are of an inferior quality and should not be used in good work; the stronger the slate the greater are its