Page:Popular Science Monthly Volume 21.djvu/588

From Wikisource
Jump to navigation Jump to search
This page has been proofread, but needs to be validated.
574
THE POPULAR SCIENCE MONTHLY.

part of the soluble vegetable matter are albuminous in character, and the chemical effect on the water is to increase the amount of what is called "albuminoid ammonia." No doubt dead fishes and animalcules and their excrement add to the nitrogenous organic matter in surface-waters, but their presence is not necessary to account for bad odors. As a rule, in waters not contaminated with sewage, the animal matter forms only a trifling proportion of the entire organic matter, but the recent investigation of Professor Remsen shows that in some instances the animal matter, as from sponges, may be appreciable and of practical importance.

 

Old and New Latitudes on the Atlantic Coast.—The Rev. Edmund F. Slafter, of the New England Historic Genealogical Society, has published an inquiry into the history and causes of the incorrect latitudes as recorded in the journals of the early writers, navigators, and explorers relating to the Atlantic coast of North America. After giving comparisons of the old with the new and corrected latitudes of a considerable number of places, he sums up bis conclusions that the early latitudes are generally trustworthy to within a single degree; that the minutes or fractions of degrees as set down by writers anterior to the middle of the eighteenth century are never to be relied upon, and are never correct, except by accident; and that the annotations of commentators upon the latitudes recorded in the journals of our early navigators and explorers, in all cases in which they attempt to identify places within the limit of one degree by the latitude alone, can not properly be cited as authority. The sources of the errors of latitude to which attention is thus directed are not far to seek. The instruments possessed by the earlier navigators were of the rudest and coarsest character. They were graduated in degrees only, of which each degree occupied but about one tenth of an inch of space, and the attempt to subdivide this space into sixty parts, for minutes, would have been impossible if it had been made. So, putting down the fractions of degrees, or minutes, was an absolute and sheer guess. In the old journals the minutes are usually written in fractions of a degree, as one fourth, one third, one half, two thirds, or three fourths, and sometimes translated into minutes, and given as fifteen, twenty, thirty, forty, or forty-five minutes, but very rarely in any number of minutes not represented by these general fractions. The zodiacal ephemeris, moreover, was not graduated in minutes, and consequently inaccuracy existed as to the exact point of the sun in the zodiac at the time of taking the latitude. The tables used in connection with this instrument, moreover, were not calculated oftener than once in thirty years, so that they became obsolete long before they were put away, by reason of the precession of the equinoxes. Several other sources of error of minor importance, now always allowed for, were neglected in those days. "If the latitudes of the early navigators," the writer adds, "had been determined with as much accuracy as is attained by the observations of the present day, some interesting historical questions might have been settled, and some not very decisive controversies might have been avoided."

 

Word-Blindness.—M. Armaignac has described a curious case of persistent "word-blindness." The sufferer is and always has been in the full enjoyment of his intellectual faculties; he has never had any trouble in his speech or from paralysis; and he writes correctly, in a regular and elegant hand, whatever is dictated to him or whatever is his own thought; but, although his vision is perfect and normal, he can not see a single printed word or a written one, whether it be written by himself or another. He recognizes the names of the letters and figures, but can not join them objectively to form words or numbers; yet he can form words and numbers mentally if the letters or ciphers are dictated to him. M. Armaignac has advised his patient to learn to read again, beginning with the alphabet; but he finds the intellectual strain of joining the letters into words and syllables very severe.

 

Harvest-Time.—Every season is a harvest-time in some country on the globe. In Australia, New Zealand, Chili, and some other countries in South America, the harvest takes place in January. In India, it