# Popular Science Monthly/Volume 44/April 1894/Correspondence

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CLOSE OF THE GLACIAL PERIOD.
Editor Popular Science Monthly:
Geologists who are only slightly versed in astronomy are apt to make a serious mistake on this subject. The latest which has fallen under my notice is by Prestwich. in the article entitled The Position of Geology, in the February number of this periodical, page 541._ He says: "The last of these astronomical periods was calculated to have commenced two hundred and fifty thousand years and to have ended eighty thousand years ago. These numbers have become stereotyped as those of the beginning and the end of the Glacial period."
A slight acquaintance with this subject ought to prevent mistakes such as the above. They are stereotyped only to those who give little or no heed to the actual dates and as little to a universal law of Nature touching the cumulative effects of constantly acting forces. These effects were clearly set forth by Prof. Le Conte some years ago in treating of this general subject. The day of the summer solstice is not the day of greatest heat or the middle of the hot season; nor is the day of the winter solstice in the middle of the cold season. The maximum in the two cases occurs about six weeks after those dates respectively, an amount about equal to one fourth of the whole time from one extreme to the other. These are elementary truths, and whoever omits them in this discussion repeats the old story of "playing Hamlet with Hamlet left out."
The following is a brief statement of the essential points in the case: Two hundred and fifty thousand years ago the eccentricity of the earth's orbit was very nearly what it is now, and consequently the climate of these two distant periods, so far as it may depend on the eccentricity, was not very different. The eccentricity had been less, but was then increasing, and had so been for ten thousand years. It continued to increase for about fifty thousand years longer, becoming then nearly three times its present value. Then for another like period it diminished till it became about once and a half its present value. Then again for a second time it increased for about fifty thousand years, becoming about two and a half times the original value. This was one hundred thousand years ago. The decline again commenced, and eighty thousand years ago the eccentricity was more than double its present value. It is therefore evident is plain as an axiom—that the Glacial period did not end then and there. The eccentricity continued to be greater than it is now for twenty thousand years more. And for this long period of one hundred and ninety thousand years the eccentricity, on the average, was more than twice what it is now. Those who disregard these facts have not fully grasped the question. It would better accord with truth to say that sixty thousand years ago the Glacial period was making ready "to go out of business."
If we allow only thirty thousand years for the undoing of the effects of the one hundred and ninety thousand—and the allowance is certainly moderate—the close of the Glacial period was only thirty thousand years ago, and that date is comparatively recent when counting geological time. It appears, then, that there is no irreconcilable difference between those geologists who reject Croll's theory by reason of the alleged remoteness of the Glacial period and those who think there "may be something" in that theory. And the more especially is this the case since the recent discovery of the old outlet of the upper lakes through Lake Nipissing and the Ottawa River and the relatively late period when the waters of all the upper lakes began to flow to the sea by way of the Niagara.R. W. McFarland.
DOG PSYCHOLOGY.
Editor Popular Science Monthly;
Dear Sir: I was greatly interested in Mr. Monteith's article on "The Psychology of the Dog," in the February number, and desire to supplement his paper with some observations of a dog of my own. The animal was a pug—not full-blooded, but with a cross of some other kind; yet he had all the characteristic markings of that breed, and his general appearance was the same, except that his nose was a trifle longer and not so stubby.
"Gyp" was intelligent to a remarkable degree, and from some of his actions I firmly believe that he not only understood what was said to him, but he was capable also of continuous thought, and could reach conclusions. That he understood many words, and could distinguish between them, I am satisfied.
His mistress taught him that when some candy was placed before him, of which he was very fond, if she said, "That's Democrat," he must not touch it, but when the word "Republican" was uttered he at once ate it.
When "Gyp" was thirsty he would go into the kitchen and sit patiently at the sink waiting for a drink; but if, after waiting for ​a reasonable length of time, no one came to supply his wants he would utter a sharp, impatient bark.
His happiest moments were when his master would ask him if he wanted to go out walking, and he would express himself very forcibly and unmistakably in the affirmative, and would, if asked at such a time, go to each member of the family, stand upon his hind legs, and give them each a kiss; or, if his master said to him, "Roll over, if you want to go walking," he would at once lie down and roll completely over.
But his reasoning or thinking powers were more clearly manifested in connection with a rubber ball with which he played, and which he would leave in various nooks and corners. When asked, "Where is your ball?" he would, if it was not in plain sight, bend his head down and stand for a moment as if in deep thought, and then proceed at once to get it, sometimes making a quick dive under the lounge, or in a bedroom, under the bed, or behind the curtains that separated the dining from the sitting room, always returning with it, and would look up into one's face, his very countenance intelligent with the answer, "Here it is."
His master generally putting him to bed at night, he usually lay upon the lounge, waiting for the time; and, after the fires had been replenished and the clock wound, he would get down and be ready to go. He invariably waited until the winding of the clock before preparing to start.
In an evil hour "Gyp" strayed away from home one day, and came back a badly used-up dog. He had evidently been attacked by some larger dog or dogs, and after lingering for nearly two weeks he died from the effects of the bites.
During this time he seemed really more like a "human being" than a brute. He was most patient and grateful for all the kind offices and helpfulness of his master and mistress, and heroically submitted to have his wounds washed and medicated, and, although at times scarcely able to walk, he insisted on being where his friends were, or where he could see them.
* J. Andrew Boyd.
* Ashley, Luzerne County, Pa.
THE "BLUE LAWS" A MYTH.
Editor Popular Science Monthly:
"The early Puritans of New England, who enacted the most ferocious of blue-laws, who would not let a man step over a stone in his path, or kiss—not his neighbor's but his own wife—on a seventh day," etc.
The above is a quotation from the very first page of an article, in the last number of The Popular Science Monthly, entitled Abolish All Prohibitive Liquor Laws, by Appleton Morgan. Now, these mythical blue laws never had any existence; no law forbidding a man to kiss his wife on the seventh day was ever on the statute-books of any New England colony. Prof. Johnston's History of Connecticut, in the American Commonwealths Series, or Palfrey's History of New England, will show the origin of this absurd myth. A glance at Blue Laws, and the Rev. Samuel Peters, in either Appletons' or Johnson's Cyclopædia will perhaps be enough for the ordinary reader.
Such careless misstatements naturally cause the reader to question the accuracy of the entire article. As you say in your editorial comments on the "young moon" error, "writers, and particularly writers on scientific subjects, are under obligations to know what they are talking about."
* Charles E. Davis.
* Washington, February 20, 1894.