Such rapid encroachments of the sea on some shores, accompanied by recession of the sea on others, alone suffice to account for great changes in the course of ages. These changes include tilting of the strata and change of the configuration of the shores. Judging by general analogy, one would infer that geological changes are of various speeds, some very gradual, others more rapid, just like the work of running water, which goes on all the time and yet may accomplish more during a single flood than during several ordinary years. There is room for both the "catastrophists" and the advocates of slow and gradual movement.
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That the presence of comets causes or indicates hot weather is an item of ancient belief, and theorists may choose between rejecting or explaining it. There is a well-known story of a philosopher, who, desirous of proving that his philosophy could, if need be, be turned to material profit, bought up some vineyards in view of a prospective comet, thus reaping the harvest of a good season. The phrase "comet vintage", as applying to wine, is also well known. A recent theory, as announced in the papers, attributes the great heat of the summer of 1911 to the presence of a comet in the solar system, the head of the comet being supposed to act like a lens and to concentrate the solar power. Whether or not this lens plays any tricks with optics, we are not told. As science progresses, more attention is paid to the influence of electric and magnetic conditions upon the weather; while recent discoveries provide us with an ample machinery of rays and emanations to act as go-betweens from celestial bodies to the earth.
This is the Dog that worried the Cat
That killed the Rat
That ate the Malt
That lay in the House that Jack built.
So says an ancient poem, and it reminds us of the "balance of nature" which people are always upsetting. If we kill the Dog there will be too many cats and they will have to supplement their rat-diet with birds. If we kill the Cat, the Rat will eat all the Malt; and if we kill the Rat, we starve the Cat. So with agriculture; one scarcely knows what to kill or what to spare. We are told now that we must avoid deep plowing, or we shall kill the Spider which worries the Grub which eats the Crop that Jack sowed. This spider is the aerial spider, a small but very numerous creature who—doesn't fly, but uses a filament of web as an aeroplane. A writer in The Technical World Magazine has studied their habits. Their webs are seen during the warm autumn days floating in countless numbers through the air; but even these are but a small fraction of the real number; for what we see are merely the ones who have made failures and got their aeroplanes caught on something. It is estimated that on cultivated grass-land there are enormous numbers of these spiders per square foot.
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As to the "old style" and "new style" calendars, people are often in doubt as to the number of days by which these differ from each other, and whether to add or subtract the days. If we remember that when the new style is adopted anywhere, days are omitted from the calendar, and the date thereby set forward, we shall see that the old style dates are always behind those of the new style, and we must add or subtract as required. The astronomer Clavius, whose work has lent immortality to the name of Pope Gregory XIII, put the calendar date ten days forward, to make up for the error which had been accumulating for centuries. This was in the 16th century. To prevent the calendar from getting wrong again, he suppressed the intercalary days (Feb. 29) three times in every 400 years, namely, in 1700, 1800, 1900, but not in 1600 or 2000, the intercalary days being thus allowed to remain in every century year whose first two digits are divisible by 4. By the time England made the change it was necessary to put the date forward 11 days, as this was in the 18th century, and the year 1700 had intervened. Those countries which have not yet adopted the change were 12 days behind in the 19th century, and are now 13 days behind. The correct way to write a date so as to represent it in both styles is, for instance, July 31 / Aug. 13, 1911; or July 31 / Aug. 12, 1831. The calendars, unless the old style is given up, will continue to differ by 13 days until March 1st, 2100.