Page:Popular Science Monthly Volume 41.djvu/581

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the East included the starting-point of the epidemic of influenza that prevailed then, it is presumed that this atmospheric condition favored its extension toward the West. The views expressed by M. Masson, of Paris, before one of the medical societies of that city, substantially agree with these. The period of greatest mortality from grip in Paris, from November, 1889, to February 1, 1890, was marked by a constantly higher pressure than the average; the temperature did not fall below 5 C.; the hygrometric condition was high, and radiation fell off from the very beginning of the epidemic. In the principal capitals of Europe, according to M. Masson's investigations, the grip coincided in general with a humid, foggy condition of the atmosphere, and only moderate cold and an unusual height of barometer. It was so at Vienna, Berlin, and Brussels. But in Russia, where the grip is endemic, the mortality increased when the barometer fell and the thermometer rose, and the mean humidity was augmented. At St. Petersburg it disappeared when the pressure rose and the cold became more intense. For all other regions M. Lang's and M. Masson's rules were verified.


The Parapee Palm.—According to a note in Garden and Forest, the Parapee palm (Guiliehna speciosa) is cultivated by the Indian aborigines of the Guianas for its fruit, which they use largely as food. They plant it about their settlements, and, where it is found apparently wild in the forests, examination will show that such situations were formerly occupied by the Indians. In some seasons the fruit is produced without seed, while in other seasons it contains seeds, the variation occurring in the fruit of the same trees from season to season. When boiled or roasted the fruit has something of the texture and taste of a dry, mealy potato. It is palatable and very nutritious. The fruits, which are individually about the size of a pigeon's egg, are borne in bunches of from forty to sixty together. There are two or three bearing seasons in a year.


Preservation of Minerals and Fossils.—Minerals and fossils are not exposed to the ravages of insects, like zoological collections; but many of them are liable to destruction by deliquescence and efflorescence. Deliquescence is the property possessed by some bodies of attracting moisture from the atmosphere and dissolving in it. There is no means of preventing these accidents, except inclosing the specimens in hermetically sealed envelopes. Efflorescence is a property possessed by other bodies of falling into powder. There are several ways of protecting specimens against it. Fossils converted into white pyrites, or the substance of which is impregnated with salts and not susceptible of being washed, should be fully dried and covered with a varnish that will not scale, and they can also be dipped in oil. Impressions in danger of being rubbed off can be consolidated by impregnating them with a thin solution of gum arabic, a little sugared to prevent its cracking. Mr. Chalande recommends for the preservation of rocks, fossils, bones, etc., liable to split or fall into efflorescence, placing them for from one to twenty-four hours, as the case may demand, in a bath, made by mixing equal parts of silicate of soda or potash and water, and drying after the bath. This gives the piece a considerable degree of hardness. For the preservation of pyritous fossils, M. Andre Fonville recommends preservation in paraffine; this, however, is only adapted to small specimens; and for fossils of considerable size, like ferns, sigillaria, etc., he advises the silicate-of-soda method. To consolidate fossil bones, M. Lambert recommends coating with boiling melted whalebone. The hot matter penetrates the pores and becomes very hard. If any of it remains on the outside of the specimen, it may be removed with blazing paper. Gelatine and strong glue, used by many persons, are good, but not so good as the whalebone application.


The "Silver Thaw."—The "silver thaw," as described by R. C. Mossman, of Ben Nevis Observatory, occurs during an inversion of ordinary temperature conditions, when the temperature is considerably lower at the surface than at higher altitudes, and the rain congeals as it falls. In the six years from 1885 to 1890, 198 cases of silver thaw were observed at Ben Nevis, with a mean duration of four hours and a half in each case. They nearly all occurred between November and March, during times of per-