Page:Popular Science Monthly Volume 4.djvu/523

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history in parallel columns, as Mr. Collier has here done under Mr. Spencer's direction, but his tables are a sufficient answer to all disbelievers in the possibility of a science of history. Where the chronicle of individual lives often perplexes and mystifies the scholar, the generalization of social principles from the chronicler's materials shows an order of human affairs where cause and effect take their inevitable course, as in Physics or Biology."


New Material for Dental Plates.—Among the novelties exhibited at the American Institute Fair is a new base for artificial teeth, the invention of a New York dentist. It consists mainly of fish-scales, which, dissolved and combined with certain fibrous and adhesive substances, form a compound that is said to be well adapted for use as dental plates. Greater strength, durability, and lightness, and freedom from all taste, are the advantages claimed for it over the materials in common use. It is capable of receiving a fine polish, and may also be readily colored to any desired tint, qualities which adapt it to a great variety of purposes outside of dentistry. It is also said to be an excellent material for waterproofing cloth.

Meteorological.—In his report for 1872, Mr. Daniel Draper, Director of the Meteorological Observatory in Central Park, considers the following points:

1. "Has the summer temperature of the Atlantic States undergone any modifications?

2. "What is the direction in which atmospheric fluctuations cross the United States?

3. "Is it possible to trace the passage of American storms across the Atlantic, and predict the time of their arrival on the European coast?"

By carefully-arranged tables, he shows that no change has taken place in summer temperature, and concludes that "the mean heat of summer and the mean cold of winter are the same now as they were more than a century ago."

These conclusions are from observations made in Boston, New Haven, New York, Philadelphia, and Charleston. It may be added that, in his former reports, it was shown that over the same areas the annual rainfall has neither increased nor diminished.

The movement of atmospheric fluctuations is illustrated by diagrams founded on observations at the Observatory, and the daily maps published at Washington. It appears that these movements are not all cyclonic—many are like waves of the ocean, long and straight, and have a forward motion. This motion over the United States is eastward. The velocity of this motion has been determined in a great number of instances for the years 1869, 1870, 1871, and 1872. During the last year the highest forward velocity was 569 miles in twenty-four hours; the lowest velocity, 82 miles in twenty-four hours. The highest velocity recorded was about 29 miles an hour, or 690 miles in twenty-four hours; this occurred on the 28th of March, 1870. The time required to cross the Atlantic varied from ten to twenty days. It sometimes happens that storms which leave our coast three and four days apart arrive on the coast of Europe together, and, in such cases, the storm is usually severe. The observations made show that, out of eighty-six storms expected to cross the Atlantic, only three seem to have failed. Moreover, it is shown that the direction of the movement is maintained, so that it may be known several days in advance what part of the coast of Europe will be covered by the advancing storm.

The great practical value of these observations and reports will be at once recognized, and the conclusions they suggest and confirm are among the most interesting of the results of modern scientific research.

Sewage Fertilization.—The following, from the report of the committee of the British Association on the "Purification and Utilization of Sewage," effectually disposes of some of the more important objections that have been urged against the use of sewage for fertilizing purposes:

"By properly-conducted sewage irrigation a solution is afforded to the question of sewage utilization. It has already been stated that a precipitation process, or some clarifying process, may be found useful: in