Page:Popular Science Monthly Volume 49.djvu/741

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719
FRAGMENTS OF SCIENCE.

feet, but the tree will not thrive if exposed to the direct influence of the sea breeze. The plants are propagated by means of the seed, which is simply covered with loam and some sort of fertilizer, and then the whole covered with banana leaves. The bed is sprinkled every day for twelve or fifteen days, when the seedlings appear. Then the banana leaves are removed, and sheds are erected over the bed, which serve as shade and shelter. A year after sowing, seedlings are about twenty inches high and ready for transplanting. The plants begin to yield remuneratively in about five years. The average annual yield of dry cacao from each tree varies greatly, but is somewhere between a pound and a half and eight pounds. The pods having been gathered are placed in heaps under the trees, to be subsequently taken to the quelradero where they are broken. The kernels or nibs are then taken out of the pods, which are either opened with a machete or a knife made from a wood called jahuate. The seeds are thrown into wooden troughs called tollas half filled with water to wash them, and the beans are then carried away to the cacao house for the sweating or fermentation process. After being properly sweated they are dried ready for shipment. It is stated that seven hundred and fifty trees will give the planter a net annual profit of more than $1,225.



MINOR PARAGRAPHS.

Prof. Dewar, in the first of a series of lectures on Chemical Progress at the Royal Institution, paid a well-deserved tribute to the pioneer work of M. Moissan, in his researches on the combination of carbon and the various metals in the electric furnace. Prof. Dewar also called attention to the fact that many years ago Mendeleef put forth the view that the immense localization of petroleum at Baku and other centers could only be accounted for on the theory that it was being continuously generated by the action of water on carbides. Benzene, which is the nucleus of all the colors hitherto obtained from coal tar products, is reached by the acetylene process in three stages: first, the combination of lime and coal in the electric furnace; second, the decomposition of the resulting carbide by water; and, thirdly, the transformation into benzene of acetylene gas by means of heat.

The catalogue of earthquakes in Russia, to which are added those in China, Persia, and other countries bordering on that empire, begun by A. Orloff, in 1869, and just completed and revised by Prof. Mushketoff, contains a list of about 2,400 separate earth, quakes which occurred in 560 places, between 596 b. c. and a. d. 1887. Of them, 710 took place in China, 549 in East Siberia^ 36 m West Siberia, 202 in Central Asia, 590 in Caucasia, 121 in Asia Minor and North Persia, and 188 in European Russia. Considering only the periods during which the observations went on without interruption, the frequency of earthquakes may be represented as having been 640 in each hundred years in Caucasia, 810 in China, 290 in East Siberia and Turkistan, 138 in Middle and South Russia, and only 19 in North Russia, Finland, and the Baltic provinces. The date of the catalogue shows that while in Siberia and Central Asia earthquakes are more frequent during the autumn and winter than during spring and summer, the proportion is reversed for China and Caucasia.

The interdependence of the most unlike things in Nature is well shown by the following: It seems that in certain districts the growing of water cresses is quite an important industry. The caddis worm is very fond of water cresses, but is usually kept from doing them any serious damage by the trout, which it seems are very fond of the caddis. But during last season a large number of herons appeared, who have a special predilection for trout, which they thinned out to such a degree that the caddis worms were given a free course, and soon destroyed the water-cress crop. The loss of the water-cress grower was primarily due to ravages of the caddis worm; which ravages were due to the lack of trout; the lack of trout being due to the unusual number of herons present in the neighborhood, and the unusual number of herons was due to the men who encouraged their breeding and multiplication for other reasons. Thus we have a state of things