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Page:Popular Science Monthly Volume 19.djvu/734

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THE POPULAR SCIENCE MONTHLY.

the extent of the terraced shores shows that this view is erroneous. Such shores have been found everywhere in high northern latitudes, so far as their wastes have been penetrated. They are also extensively found, but generally diminishing in height, down in the temperate latitudes. In other words, around the north pole, and far down toward the south, the sum of the negative movements of the coast-lines is greater than the sum of the positive movements, but the sums become more nearly equal as we come south. The opposite is the case in the tropical waters, in the regions of the coral reefs, where the sum of the positive movements is in excess. Farther to the south, beyond the twenty-fifth to the thirty-fifth parallels of latitude, there begin again to appear, in South America, in South Africa, Southern Australia, and New Zealand, terraced lands like those of the north, the same excess of negative movements, the same signs of oscillation, as in the north. The gradual tendency to a higher exposure of the land toward both poles has been noticed in single large tracts by many observers in North America, in England, Scotland, Scandinavia, China, Australia, and South America. When we consider as a whole the character and extent of these movements, as recent observations have defined them, and regard the compensatory results of the excess of positive movements toward the equatorial regions, and of the negative movements toward the neighborhood of the poles, we shall be convinced that we should no longer speak of an inexplicable oscillation of the lithosphere. We have, in fact, to do with continuous changes in the figure of the fluid covering of the earth. Since the epoch of the maximum of cold, which Hochstetter believes came upon both hemispheres at once, an excess of positive results has taken place in the direction of the poles, causing an accumulation of water around them, and this has been followed by an accumulation in opposite directions, or toward the quator, causing a change of form which is still going on.

 

Persian Opium.—The production of opium has greatly increased in Persia within the last two years, and the quality of the drug has been correspondingly improved. Previous to 1876 the average annual production was about 2,000 cases, and the largest return in one year did not exceed 2,600 cases. The amount for 1878-'79 was 6,700 cases, and the estimate for 1879-'80 is for 7,100 cases. Great care is now taken to prevent adulteration, but this does not appear to be always essential. Five sixths of the product is sent to China. For this market the drug must be fine and prepared in oil, but need not be rich in morphia. It can be largely swelled up with foreign substances, with but little danger of detection by the testing processes in use there. It is said that pure and superior opium, though not so finely manipulated, has been rejected in China, while the fine opium, containing admixtures, has found favor and a fair market. The preparations intended for England are made especially pure, and yield an average of about twelve per cent, of morphia, while those intended for China yield from nine to ten per cent.

 

Mortality in Different Pursuits.—The reports of the British Registrars-General show that the annual death-rate in the United Kingdom is about one in forty-five of the entire population. The larger, but not the largest, towns lead in the rate of mortality, and the rural mainland districts occupy an intermediate place between them and the insular districts, the extremes varying by about fifty per cent. As between the three great classes into which the population may be divided the laboring, the trading and professional classes, and the gentry and titled the chances of life are very nearly equal, although a slight advantage appears to be shown in favor of the first class. The trades most unfavorable to long life are, as a rule, those which tend to expose the operative to an atmosphere loaded with dust, or compel him to deal in one way or another with poisons. Dry grinding, as practiced on needles and forks at Sheffield, is the worst; working in coal-mines is next in deadliness. Gilders and silverers of glass are exposed to vapors of mercury; workers in brass are liable to diseases produced by exposure to volatilized oxide of lead; all who work in paints are subject to great risks; soldiers and sailors have their lives shortened by the exposure they have to undergo, or by diseases