Page:Popular Science Monthly Volume 2.djvu/785

Rh 1852 was looked for with great interest, and it was then seen that its two fragments had not only remained apart, during the interval, but that the distance between them had increased. In 1859 no observation could be taken, and in 1866, though the circumstances were eminently favorable, no comet was seen. The same thing occurred again in September, 1872. But, when the earth's orbit, on November 29th, intersected that of the comet a few weeks later, after the passage of the latter, it was expected that we should have a view of the meteors forming its dispersed train. And such was the fact, as the records of astronomical observation all over the world show. "As the meteors of this cluster," concludes Prof. Kirkwood, "are doubtless the débris of Biela's comet, if we find the epoch at which the original body would have crossed the earth's orbit near the 29th of November, we may regard the collision of our planet with some of the large fragments—and hence a grand meteoric display—as highly probable at the same period. An easy calculation, which need not here be repeated, gives the last of November, 1892, as such an epoch."

Temperature in Disease.—In health the temperature of the human body is but slightly variable, rarely oscillating beyond one or two degrees on either side of 99° Fahr. In disease, however, the variations are greater, and in the disorders of young children wider even than in those of the adult. The temperature in grown persons has been observed to fall to 95° Fahr., and to rise as high as 107° Fahr., giving a range of 12°; and these are regarded as the extreme limits of variation in the ailments of adult age. In the sickness of children, according to M. Roger, the temperature sometimes falls to 74.3° Fahr., and may rise to 108.5° Fahr., which is equivalent to a range of 33.2°. In the typhoid fever of infants, the temperature in the majority of cases attains or passes 104° Fahr. Of the eruptive fevers, it rises highest in scarlatina, sometimes reaching 105.8° Fahr., next highest in small-pox, and in measles the least of all.

Among the diseases characterized by a fall of temperature below the normal standard, Roger observed in six cases that the mercury sank to 78.8°; in other cases the depression reached respectively 77°, 73.4°, 72.5°, and in one instance to 71.6°, or 27.4° below the temperature of health.

Hansen's Writing-Ball.—Under the title of "A New Writing-Machine," we alluded in a former number to the character of this invention, which during the past season has elicited a great deal of admiration both in the Copenhagen Exhibition and in London. Since first introduced to the public, it has been very materially improved, and now not only furnishes superior facilities for writing, but is admirably adapted to the purposes of copying as well. In the improved machine, the paper rests on a level surface, so that the operator is at all times able to see what he writes, and less time is lost in adjusting and removing the sheet. By interposing carbonized paper between the sheets, and making all move together, several copies may be written or printed off at a single operation. It will thus perform the duty of several copying-clerks, and has also been found admirably suited to the work of writing out telegraphic dispatches.

Mental Labor and Health.—The Lancet reverts to the question of mental labor and longevity, in order to correct some misapprehensions of its recent articles on that topic. "Intellectual activity," persists the Lancet, "is a preserver rather than a destroyer of nervous health: but this holds true only when the conditions of ordinary hygiene are not outrageously violated." If, coupled with the intellectual strain, we have harassing anxiety, sleeplessness will result, and this is fatal. But suppose there is no such anxiety, but merely ardor for work, then a man might easily transgress the plainest laws of health. The minimum of sleep required by the adult male in twenty-four hours, according to the Lancet, is six hours, and by the adult female, seven. As for night-work, the Lancet does not think it injurious per se. The light should be very white, powerful, and steady, otherwise there will be brain-irritation. The intellectual worker must obey implicitly the reversed scriptural law: "If a man will not eat, neither shall he work." He must take abundant nutriment, at proper times, together