Page:Popular Science Monthly Volume 10.djvu/780

 storm, in or near the general direction of its motion.

At stations northward of latitude 36°, observations show that great rains are accompanied by easterly winds; but, at the more southern stations of the district, the winds are north of east; while, at the northern stations, the winds are from south of east. When the wind blows from any other quarter, it is usually light.

This paper, like others previously published, presents, with the diagrams which have been published with them, the general phenomena of atmospheric movements with clearness and precision, and will speedily supersede the vague speculations concerning them which have so much occupied the public mind.

A Rapacious Fish.—The Serrasalmo piraya, found in all the rivers of Guiana, is doubtless one of the most voracious of fishes. The genus Serrasalmo (literally "serrated salmon," because of the double row of serratures on the belly) can hardly be classed with Salmonidæ, from which they differ both in general appearance and in habits. The S. piraya is a small fish, seldom exceeding one foot in length, but yet there is no animal that it will not attack, man not excepted. Alligators, horses, as well as fishes oftentimes ten times their own weight, are preyed upon by the pirayas. In attacking a fish they begin at the caudal fin, and the victim, being thus left without the principal organ of motion, is devoured with ease, several pirayas sharing in the meal. They often bite a piece out of a horse's leg when passing through the water. The feet of ducks and geese which are kept in the neighborhood where pirayas are plentiful, are almost invariably cut off, and the young ones devoured. In such localities it is unsafe to bathe, or even to wash clothes, in the river, many cases having occurred of fingers and toes being cut off by them. Schomburgek, in his "Travels in South America," from which most of these particulars have been derived, states that these fishes are "caught with hook and line, and their greediness is so great that no art is necessary to conceal the bait. The hook may be baited with a piece of fish, bird, or animal, or merely their entrails; the piraya will dart at it the instant it is thrown into the water, and seize it with eagerness, but it frequently happens that with its sharp teeth it bites the line, and escapes with the hook in its mouth. We, therefore, surrounded the line where it was fixed to the hook, the length of two or three inches, with tin or lead, and though it had a clumsy appearance we were not less successful. Some precaution is necessary even after the fish has been lifted out of the water, or it will inflict in its struggles serious wounds; the angler has, therefore, a small bludgeon ready, wherewith its skull is broken."

Science and Ventilation.—Sundry members of the Paris Academy of Sciences, at a recent session, expressed themselves very strongly as to the defective ventilation of the hall in which their meetings are held. Said M. Bouley: "The air here is unfit to breathe; the thing admits of no excuse; instead of gas, I wish we had again candles, as in former times." M. Leverrier: "I asked for lighting with gas, but I had also asked for another mode of ventilation; but, with regard to this, there has been no change. However, General Morin is a member of the Academy, and, in eight days, proper apparatus for ventilation might be set up, if we so wished." General Morin: "Eight days! Ten years ago, the setting up of such apparatus was in principle decided on." Leverrier: "The present condition of things is simply disgraceful; no other hall is so badly ventilated as the hall of the Institute." The eminent astronomer, were he to inspect critically the assembly halls of scientific and legislative bodies in other countries, would doubtless find abundant reason for retracting this severe judgment.

Intestinal Calculi in Horses.—In England and Continental Europe large numbers of horses die annually from the effects of calculi in the large intestine or in the cæcum. Of these calculi, Dr. T. L. Phipson writes in the Chemical News that they often begin by being triangular, or sometimes perfectly square, with rounded edges and corners, and become finally circular. In all cases they are formed of