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118
THE POPULAR SCIENCE MONTHLY.

Rome at a very early period, while a similar liquor still forms the chief beverage of all African nations, being now, as formerly in Egypt, fermented by means of plants. In China and Japan rice was and is used to make wine or beer instead of wheat or barley or American maize. The sour milk or koumiss of the pastoral tribes of Central Asia, and the mead of the ancient Scandinavians, both reappear among the Kaffirs of South Africa. Palm-wine is used wherever palms flourish, but wine of the juice of the grape, although known in very ancient times, seems to have been confined to the civilized races of Western Asia and Egypt, extending later to Greece and Rome. The multitude of wines described by Pliny were, however, in almost all cases flavored with herbs or garden-plants for medicinal purposes. The conclusions to be drawn from the history of fermented beverages, as recorded by travelers, are, that the earliest stimulants were simply leaves and roots chosen by animal instinct, chewed, and found by experience to produce exhilaration and strength. The art of distillation, though probably known early in the Christian era, is comparatively modern, and was certainly unknown to savage races until "fire-water" was introduced, to their serious detriment, by Europeans.

In a paper on the "Shifting of the Earth's Axis," Mr. A. W. Waters pointed out how the unequal distribution of land and sea might be an agent for preventing the movements of elevation and depression of the land in one part of the globe balancing those in another, and also showed how similar movements in various localities would differently affect the pole. Any movement, such as submarine elevation, which displaces water, would spread it over the oceanic area; and the effect of this would, with the present configuration, be the same as if about one-twelfth of the weight had been added in the northern hemisphere along east longitude 45° 44', namely, in a line passing by the entrance of the White Sea, over the Caucasus, and through the middle of Madagascar. As every submarine movement would create a force acting in this direction, there seems reasonable ground for thinking that the tendency would be for the shifting of the axis to take place near this line.

Simultaneous Contrast of Colors.—An incident in the life of Henry IV. of France finds its explanation in an experiment made by Chevreul. While yet Prince of Navarre, Henry IV. was playing dice with two courtiers a few days before the massacre of St. Bartholomew's-day. They saw, or thought they saw, on the dice spots of blood; and the party broke up in alarm. The phenomenon is explained by Chevreul by the law of simultaneous contrast of colors, and he illustrates this by experiment as follows: Seat yourself in a room so as to receive on the right side the sun's rays at an angle of 20° to 25°, the left eye being closed. On a table covered with gray paper and under diffuse light place two hen's-feathers, one black and the other white, distant 0.6 to 0.8 metre from the eye. After about two minutes, with the right eye in the sun's beams, the dark feather appears red and the white one emerald-green. After a few seconds the black feather of red color seems edged with green and the white feather seems of a rosy color. Now close the right eye and open the left. The black feather will be black and the white one white. The effect is evidently due to insolation: the black feather appears red because it reflects much less light than the white feather. From the law of simultaneous contrast of colors, the insolated eye seeing the green by white light, the black feather must appear of the complementary color of green, which is red.

Constitution of the Nebulæ.—Mr. E. J. Stone, in a paper read before the Royal Society, London, attempts to reconcile Huggins's discovery of bright lines in the spectra of nebulæ with the old view that nebulæ are irresolvable stellar clusters. The sun, he remarks, is known to be surrounded by a gaseous envelope of very considerable extent. Similar envelopes must surround the stars generally. Each star, if isolated, would be surrounded with its own gaseous envelope. These gaseous envelopes might, in the case of a cluster, form over the whole, or a part, of the cluster a continuous mass of gas. So long as such a cluster was