Page:Popular Science Monthly Volume 12.djvu/508

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equal, and the earth must fall below the tangent .12144 in order to keep its proper distance. The same is true of the moon: in going from C to A it falls below the tangent at C.0538 of an inch, and then is at the same distance from B as it was at C—i. e., B C and B A are equal. Prof. Schneider's

PSM V12 D508 Gravity calculations on tides.png

way of combining these numbers is unique. It is as if the moon had dropped toward the sun first .12084 of an inch, then .05386, while the earth had dropped toward the sun only .12144 of an inch. But Nature does not proceed in that way. The .05386 is a part of .12084, as the figure plainly shows. The .05386 is the moon's distance at A below the dotted line drawn from C, and .12084 is the moon's distance at A below the tangent drawn from M. It is easy to see that the latter includes the former. In the interest of science allow me to protest against such theories and such mathematics.

It is eminently right that we all should be earnest seekers of the truth, and it may not be out of place to suggest that the search should be diligently prosecuted till the truth is found, after which there will be ample time for its publication.

R. W. McFarland,
Professor of Mathematics and Civil Engineering, Ohio Agricultural and Mechanical College.
Columbus, Ohio, November 24, 1877.

We can give no more space to this controversy.—Ed.




To the Editor of the Popular Science Monthly.

Sir: May I be permitted to point out certain passages in the kind and careful review of my essay on the "Question of Rest," just published in your valuable journal, in which it seems to me that the reviewer has misunderstood the drift of the statements he criticises? Accepting entirely the general criticism on "the defects due to hasty preparation," I am yet loath that this haste should be made to appear to have had a wider influence than is really the case.

On page 242 the reviewer observes that the "author traced this result—painful menstruation—to a want cf occupation; while we should explain the lack of occupation by the incapacity resulting from the periodical pain." I believe the essay is guiltless of such an absurdity in physiological reasoning as an attempt to trace pain directly to a negative circumstance, which could only have an influence through the medium of various physiological conditions more or less directly associated with it, and hence induced by it. The inference drawn by the reviewer from the statistics is certainly incorrect, for the "unoccupied persons" referred to were so because their fortune rendered paid labor unnecessary, and for this reason it had not been undertaken. The cases where work, once begun, had been forcibly interrupted by an acquired habit of menstrual suffering are contained in the tables of painful cases.

The reviewer, page 242, second column, says that the essay admits "that, in regard to rest, the above data do not suffice to inform us of its influence," and goes on to conclude therefore that, "so far as the main theme of the book is concerned, the author leaves the question of rest in just the condition in which she found it." The statement quoted from the essay loses its real meaning by its abbreviation. It is not asserted that the data from the tables throw no light on the "question of rest," but only that from them we can have no means of deciding how far those women who acquired the habit of menstrual pain might have escaped it, had they from the beginning "rested" during menstruation, since in no case was rest found to be taken until it had become unavoidable. But the fact that so