Page:Popular Science Monthly Volume 20.djvu/417

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Messrs. Editors.

T is due to the trustees of Mammoth Cave to state that, while guarding their property rights, they have uniformly encouraged scientific investigation. Certain maps may have been modified and others suppressed; but, on the other hand, it should be noted that Manager Klett, with authority from the trustees, let me exhibit before the American Association the results of his own accurate survey of the cave, which it is his intention to publish when it is completed, in a form that can be depended on for all scientific ends. He laid no restraint on the members of the Association who visited the cave, at the close of the Cincinnati meeting, but allowed them to use barometers, pedometers, and other instruments. I regarded his request as reasonable that I should not give the scale on which his map is drawn, nor my own table of distances. The dimensions of domes, pits, and several large chambers were given, and other particulars of interest, that could not have been obtained but for the liberal aid of the manager.

Let me add, as to the temperature of the cave, that the maximum is 56° Fahr., the minimum 52°, and the annual average 53°. The latter may also be taken as the mean temperature of the earth's crust in the locality of the cave, namely, latitude 37° 14' 5"; longitude west from Washington, 9° 4'; and at an elevation of about five hundred feet above the level of the sea.

Please make the above corrections in your very gratifying report of my remarks before the American Association, and oblige,

[It is proper to add that, in making up our notices of the papers read at the last meeting of the American Association, we had to depend largely upon the reports of the proceedings in the daily papers, which are often imperfect in many points, and can not always be relied upon as correctly representing the author's meaning.—]

Messrs. Editors.

the December number of the "Monthly" I have coupled the names of Torel and Dana as believing that Greenland was the source of the American ice-sheets. If I had read Professor Dana's remarks more carefully, I should have discovered that he pronounced this view "absurd." Furthermore, in referring to the Canadian highlands as the starting-point of this ice, the early view of the same author was mentioned, but not the later one. Since 1873, Professor Dana has taught that the ice probably flowed from the Canadian (Laurentian) high-lands across the St. Lawrence Valley into New England over the higher mountains, upon a lower over a higher level to the sea; and the motion was occasioned in great measure by the enormous ice accumulations of the north overflowing southerly. I regret exceedingly the misstatements.

Messrs. Editors.

page 267 of the December number, at the bottom of the first column,

should read—

The Cincinnati members present at Boston were counted from Ohio, the Boston members at Cincinnati from Massachusetts. E. November 24, 1881.

Messrs. Editors.

The following inscribed objects have been found within the limits of the United States;

1. The Grace Creek stone, West Virginia. 2. The Pemberton axe, Pemberton, New Jersey. 3. The Davenport slates, Davenport, Iowa. 4. The Piqua tablets, Piqua, Ohio.

It is evident that, if they are authentic, they are of immensely more importance than implements or pottery.

If they are "archæological frauds," gentlemen who follow that branch of science should lend their aid to convict them.

Under these circumstances, and having devoted as much time to the study of this particular branch as any person with whom I am acquainted, I take the liberty, in the interest of knowledge, to ask an expression