Littell's Living Age/Volume 134/Issue 1732/Miscellany
The Cycloscope — It is well known that if a mirror be attached to a vibrating tuning-fork, and a point of light which moves uniformly in a plane at right angles to that in which the fork is vibrating be reflected from this mirror, the image will be an ordinary single wave. Again, if a series of luminous points move uniformly with such velocity that a point passes over two intervals during an odd number of vibrations of the fork, the two waves overlap and produce a double figure of the form of a series of figures-of-eight. Extending these principles, Professor McLeod and Lieutenant G. S. Clarke have recently constructed an ingenious apparatus which has been described before the Royal Society under the name of the cycloscope. Equidistant perforations are made in a circle on a disc, which is attached to a rotating axis, and the light passing through these apertures falls upon a vibrating tuning-fork of known period, whence it is reflected on to a screen; and from the shape of this reflected image the rate of rotation can be deduced. Hence the cycloscope promises to become of much value in determining the speed of machinery. On the contrary, if the speed at which the cylinder rotates be known, the pitch of the tuning-fork may be ascertained. Proc. Roy. Soc, April 19, No. 180, p. 157.
Capturing Ostriches — The greatest feat of an Arab hunter is to capture an ostrich. Being very shy and cautious, and living on the sandy plains, where there is little chance to take it by surprise, it can be captured only by a well-planned and long-continued pursuit on the swiftest horse. The ostrich has two curious habits in running when alarmed. It always starts with outspread wings against the wind, so that it can scent the approach of an enemy. Its sense of smell is so keen that it can detect a person a great distance long before he can be seen. The other curious habit is that of running in a circle. Usually five or six ostriches are found in company. When discovered, part of the hunters, mounted on fleet horses, will pursue the birds; while the other hunters will gallop away at right angles to the course the ostriches have taken. When these hunters think they have gone far enough to cross the path the birds will be likely to take, they watch upon some rise of ground for their approach. If the hunters hit the right place and see the ostriches, they at once start in pursuit with fresh horses, and sometimes they overtake one or two of the birds; but often one or two of the fleet horses fall, completely tired out with so sharp a chase. Newspaper Paragraph.