Page:Popular Science Monthly Volume 18.djvu/275

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Messrs. Editors.

your July issue, I find a communication from Mr. Kirkwood, of Bloomington, Indiana, in regard to a deposit of dust that was observed there on the 28th March, 1880, and in which the theory is advanced, to account for its origin, that, since a similar phenomenon occurred in Europe almost simultaneously, both may be of common origin.

The following is collated from the "Weather Review" (the official organ of the United States Signal Service) for March, 1880, and it undoubtedly leads us to infer that the Bloomington phenomenon and those treated in the "Review" were identical:

No. XV.—This area appeared in British Columbia, the afternoon of the 24th; Portland barometer 0·46, and Fort Benton barometer 0·45 below the normal. Moving southeastward, it was in Idaho the morning of the 25th, and by an easterly path was central in Nebraska the afternoon of the 26th, Omaha barometer 0·75 below the normal; at that time the pressure in the entire Missouri and upper Mississippi Valleys ranged from 0·40 to 0·75 below the normal. At midnight the area was central in Iowa, at which time the pressure over the greater part of the lower Missouri and upper Mississippi Valleys was 0·60 below the normal. At that time brisk easterly winds prevailed in the entire lake-region and Mississippi Valley generally, accompanied by rain, and brisk northerly winds from the Missouri Valley westward. On the morning of the 27th the area was central in eastern Iowa—Davenport barometer 1·04 below the normal—in the afternoon in northern Illinois, and at midnight in northwestern Ohio. During the day violent wind-storms (see data regarding local storms) occurred in the upper Mississippi and lower Missouri Valleys, and in the upper lake-region, westward from the Mississippi Valley to the Rocky Mountain slope, but little or no rain falling; remarkable dust-storms prevailed. Las Cruces, New Mexico, 26th, very violent sand-storm, filling the air with dust. Leavenworth, Kansas, 27th, blinding dust-storm, almost obscuring the sun at 10 Fort Davis, Texas, violent sand-storm. Ringgold, Ohio, 27th, heavy wind and hail storm. Professor Nipher, of St. Louis, Missouri, reports this storm "as the most remarkable phenomenon of the month. It covered the entire State, except the extreme southern part. The atmosphere was filled, during the whole day, with a fine grayish dust, which, in the western part of the State and in eastern Kansas, was so dense as to obscure the light of the sun, and to render objects invisible at a distance of from one to three hundred yards. The wind was very high, coming in most cases from the west and northwest."

Messrs. Editors.

me to say, respectfully, that Mr. Spencer impairs the public confidence in his conclusions by inattention to the reliability of what he states as facts. It is not enough that an author can cite book and page of some other writer in exact confirmation of his words. Responsibility for the truthfulness of the statement, which is the main thing, must rest upon him who repeats as well as on him who first puts it forth. A teacher of philosophy, especially, is bound to acquire a critical knowledge of the facts he uses, and to employ this knowledge judiciously for the benefit of those he attempts to instruct. In Mr. Spencer's preliminary article upon "Political Institutions," in the October number of "The Popular Science Monthly," the following statement occurs at page 6: "Having great cities of one hundred and eighty thousand houses, the Mexicans had also cannibal gods; . . . and, with skill to build stately temples big enough for ten thousand men to dance in their courts, there went the immolation of twenty-five hundred persons annually, in Mexico and adjacent towns alone, and of a far greater number throughout the country at large."

A few words concerning the one hundred and eighty thousand houses in the pueblo, not the city of Mexico. There is some difference in the estimates of the population of Mexico found in the Spanish histories, but several of them concurred in the number of houses, which, strange to say, is placed at sixty thousand. Zuazo, who visited Mexico in 1726, wrote "sixty thousand inhabitants," not houses (Prescott, "Conquest of Mexico," vol. ii, p. 112, note); the anonymous conqueror, who accompanied Cortes, says "sixty thousand inhabitants" "soixtante mille habitans" (A. Tarnaux-Campans, vol. x, p. 92); but Gomara and Martyr wrote "sixty thousand houses," and this estimate has been adopted by Clavigero ("History of Mexico," Cullen's translation, vol. ii, p. 360); by Herrera ("History of America," London edition, 1725, Stevens's translation, vol. ii, p. 360), and by Prescott ("Conquest of Mexico, vol. ii, p. 112). Solis says "sixty thousand families," instead of houses or inhabitants ("History of the Conquest of Mexico," London edition, 1738, Townsend's translation, vol. i, p. 393). This guess would give a population of three hundred thousand, although London at that same time, after centuries of growth, contained but one hundred and forty-five