ANEMOMETER

ANEMOMETER, a Machine wherewith to measure the Strength of the Wind. See WIND.
The Anemometer is variously contrived.
In the Philosophical Transactions, we have one described, wherein the Wind being supposed to blow directly against a flat Side, of Board which moves along the graduated Limb of a Quadrant; the Number of Degrees it advances, shows the comparative Force of the Wind. Walchius gives the Structure of another, which is moved by means of Sails, like those of a Wind-Mill; which raise a Weight, that, still the higher it goes, receding further from the Centre of Motion, by sliding along an hollow Arm fitted onto the Axis of the Sails, becomes heavier and heavier, and presses more and more on the Arm, till being a Counterpoise to the Force of the Wind on the Sails, it stops the Motion thereof. An Index, then, fitted upon the same Axis at right Angles with the Arm, by its rising or falling points out the Strength of the Wind, on a Plane divided, like a Dial-plate, into Degrees. See its Figure, Plate Pneumatics.
The Word is compounded of the Greek ἄνεμος, Wind, and μέτρον, Measure. ANEURISM, Aneurisma, in Medicine, a soft yielding Tumor, formed of Blood extravasated and spread under the Flesh, by the Rupture or Dilatation of an Artery. See ARTERY, and TUMOR. Aneurisms usually proceed from an Artery being accidentally cut, or pricked in bleeding; or from some preternatural Distention, or a Corrosion of its Coats, etc. See PHLEBOTOMY. If an Artery happen to be cut, the Blood gushes out impetuously, by starts; and is not easily stopped: an Inflammation and Discoloration of the Part succeeds, with a Tumor, and Inability to move the Part. The Symptoms are nearly the same in case of a Corrosion of the Coats of the Artery, only less violent. See WOUND. If the Blood ceases to flow from the wounded Artery, and pours itself Between the Interstices of the Muscles; recourse is had to manual Operation; which being neglected, the Extirpation of the Limb frequently becomes unavoidable—An Aneurism from a Distention of the Canal, is seldom fatal; though reckoned, when large, incurable: The chief Inconveniences are the Magnitude of the Tumor, and the Pulsation. See HAEMORRHAGE. M. Littre gives us the History of an Aneurism of this kind, in the Aorta; the Cause whereof he attributes to an extraordinary Diminution of the Cavity of the Axillary and Subclavian Arteries. Hist. de Acad. R. An. 1712. Another History of an Aneurism of the same Part, we have in the Philosophical Transactions. It was occasioned by some violent Shocks the Patient received on the Breast, which threw him into spitting of Blood, and soon after formed the Tumor, whereof he died. Upon Dissection, the Aneurism was found so big, that it filled the whole Cavity of the Thorax on the right Side. N° 265. The Word comes from the Greek ἀνεύρυσμα, dilato, I dilate.

ANEMOMETER