Upon the shaft or axis of the propeller wheel, or upon a shaft geared therewith, there is a hermetically closed tube or receptacle, D, which is placed at right angles with the shaft, and preferably so that its longitudinal axis shall intersect the axis of said shaft.  In this tube or receptacle is placed a weight, such as a ball, which is free to roll or slide back and forth in the tube.  The effect of this arrangement is, that as the shaft revolves, the weight will drop alternately toward opposite ends of the tube, and its stroke, as it brings up against either end, will be distinctly heard by the observer as well as felt by him if, as is usually the case, the apparatus when in use is held by him.  By counting the strokes which occur during a given period of time, the number of revolutions during that period can readily be ascertained, and from that the velocity of the current to be measured can be computed in the usual way.

When the apparatus is submerged in water, by a rope held by the observer, it will at once adjust itself to the direction of the current.  The force of the current, acting against the wings or blades of the propeller wheel, puts the latter in revolution, and the tube, D, will be carried around, and the sliding weight, according to the position of the tube, will drop toward and bring up against alternately opposite ends of said tube, making two strokes for every revolution of the shaft.

[Illustration]

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THE FLOWER INDUSTRY OF GRASSE.

A paper on this subject was read before the Chemists’ Assistants’ Association on March 8, by Mr. F.W.  Warrick, and was listened to with much interest.

Mr. Warrick first apologized for presenting a paper on such a frivolous subject to men who had shown themselves such ardent advocates of the higher pharmacy, of the “ologies” in preference to the groceries, perfumeries, and other “eries.”  But if perfumery could not hope to take an elevated position in the materiae pharmaceuticae, it might be accorded a place as an adjunct, if only on the plea that those also serve who only stand and wait.

Mr. Warrick mentioned that his family had been connected with this industry for many years, and that for many of the facts in the paper he was indebted to a cousin who had had twenty years’ practical experience in the South, and who was present that evening.

GRASSE.

The town of Grasse is perhaps more celebrated than any other for its connection with the perfume industry in a province which is itself well known to be its home.

This, the department of the Alpes Maritimes, forms the southeastern corner of France.  Its most prominent geographical features are an elevated mountain range, a portion of the Alps, and a long seaboard washed by the Mediterranean—­whence the name Alpes Maritimes.