# Page:Popular Science Monthly Volume 12.djvu/244

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THE POPULAR SCIENCE MONTHLY.

.053865275+, the fractional part of an inch as the distance the moon falls from a tangent to its orbit in one second of time. Multiply this by the square of 60, and we get, when reduced, 16.159+ feet, the distance the moon descends in one minute, which is equal to 15.1+ Paris feet, the result obtained by Newton in his "Principia."

The distance the earth falls, in one second of time, toward the sun is about .12144+ of an inch, and the distance the moon falls toward the sun in one second, when in opposition, is about .12084 of an inch. This, added to the distance the moon falls toward the earth in one second, makes .17470 +. Now, .17470 ${\displaystyle -}$ .12144 ${\displaystyle =}$ .05326. Hence the moon, when in opposition, moving faster toward the earth than the earth does toward the sun, by .05326 fractional part of an inch in a second, these two bodies have a tendency to get nearer to each other in this position. The same can be proved when the moon is in conjunction.

Now let us see how this same law affects the waters of the ocean. The earth moves toward the sun .12144 part of an inch in a second. The waters of the earth, on the side turned away from the sun, are only 4,000 miles farther from the sun than the centre of the earth. Gravity toward any body diminishes as the square of the distance increases. Hence these waters, influenced by the gravitating power of the sun alone, and not hindered by any intervening object, would fall toward the sun .12143 part of an inch in one second. Hence the earth has a tendency to move away from the waters with a velocity of .00001 part of an inch in one second—that is, if these waters were not influenced by the gravitating power of the earth, and only by that of the sun, the earth would be "pulled away" from its waters at the rate of only the 100,000th part of an inch in one second. But it must be remembered that the waters gravitate, in addition to this, toward the earth at the rate of 16.15+ feet in one second, and therefore these waters are depressed by gravity, and not elevated. The same may be proved in regard to lunar tides.

I close by saying that I am an earnest seeker of truth, and nothing but a sincere desire for truth has impelled me to write these two articles. Any person attempting to prove me in error, with the same good motive, will be kindly welcomed.

 MODERN SUPERSTITIONS.

MOST people accept it as a fact that superstition went out with the advent of steam, the telegraph, and the penny-post. A little honest observation, however, will assure us that there still exist a number of pitiable though petty superstitions. Among certain classes there are lucky and unlucky days in their calendar. They