Progress in Science.

New Zealand Graphic, Volume XLIV, Issue 25, 22 June 1910, Page 42

Progress in Science.

Detecting the Reckless Motorist.

AN INGENIOUS INVENTION.

ryi » VERY ingenious instrument / I for recording the speed and r - 1 license numbers of an automobile has been devised by two instructors of the Massachusetts Institute of Technology. The instrument, which is but little larger than a pocket kodak, consists of a double camera with a watch movement, which controls ths operation of the camera shutter. When an automobile pa-iscs at a speed that seems excessive, the operator trains the instruments upon it and releases the mechanism by pressing a button. Immediately tile shutter of the upper camera is sprung, taking a photograph of the receding automobile, and a moment later the other shutter is sprung, taking a second image of thb automobile, whereupon the timing mechanism comes to a stop. The plate is developed by the regular process, ano the resulting negative shows an image of the automobile near the operator with its license number distinct and a second view of the machine taken at the end of the time interval. In the centre of the print are the photographs of the hands of the stop watch caught when the first and second exposures were made.

Since the automobile has traversed a certain space in the time interval, the second image is isnnller than the first by an amount which can easily be measured with an ordinary scale, divided ii hundredths of an inch; and knowing that the standard wheel tread is 50 inches, the distances of the two objects from the earner i and hence the space the automobile bins covered in the time interval is easily found by the following law: The distance of any object from the lens is as many times greater than the focal distance of the camera as the length of any line of the real object is greater than its length in the photograph. This is a simple proportion in which three of the terms are known, namely, the size of the object, the size

of the image of the object on the plate, and the distance of the image from the lens. The fourth term of the proportion, the distance of the object from the lens, follows by simple division. However, the operator is saved all irksome computations by a table attached to the instrument. To overcome the possible objection by the courts, the watch has been designed so that the operator- of the instrument may actually see it during the process of taking the picture. This is made possible by simply boring a hole from the outside of the camera box to the back of the watch, which brings to view a dial around which travels a hand attached to the same pinion or staff as the regular hand of the watch. In order to see this dial more plainly, two mirrors have been placed permanently in such a manner as to illuminate it. The instrument gives extremely accurate results, and can be calibrated from time to time on objects.of known speeds. The inventors believe that the instrument should be welcomed by autoists as well as police. It is an impartial judge, the personal element being entirely eliminated. A motorist who has been stopped does not have to rely on an officer’s estimate of the speed, nor on the speed claimed by the officers operating a trap .by means of stop watch and signals. Dozens of motorists are fighting cases every day who honestly believe that they were not overspeeding when stopped. They would be perfectly willing to pay their fines if convinced they were violating the law. Even where the more rational view is taken that the speed alone shall not determine whether or not a man is violating the law, but that the speed taken in connection with the surroundings shall determine it, it is always a question of the officer’s word against the autoist’s as to surroundings. This photographic speed recorder shows whether there were several vehicles near the automobile, whether people were crossing the street, whether it Was more than ordinarily dangerous to run at the speed indicated, or more than ordinarily safe. A great advantage of the instrument is that it records speed over a short distance. In the congested portions of cities, near crowded cross streets and in similar situations, it offers the only existing method of measuring momentary bursts of speed. The record of any reckless driver can be easily obtained, and a print sent directly to him, when he cannot deny the evidence of his own eyes, and in many cases an arrest will not be necessary, as the offence will not be repeated. Regarding the legality of this speed recorder, in a recent case that was strongly contested Judge Hammond, of the Massachusetts Supreme Court, said: •‘The result of the evidence did not depend- upon the fluctuations of human agencies nor on conditions where relations to results were uncertain, but upon the immutable working of natural laws; and upon the evidence the presiding judge may well have found that' such experiments were likely -to be more reliable as to the speed of the automobile than the conjectural statement of an eyewitness or the interested statement of a chauffeur.” <?><s> <s> The New Gospel of Sleep. The new gospel of sleep which some doctors are spreading has found converts’even in the busiest haunts of New Yorkers. It is not the hand labourer alone who finds the midday nap a refreshment. There are some busy brain workers who take a nap some time between 12 o’clock and 2 as regularly as they take luncheon, and there are others who strictly live up to the injunction, ‘‘lf you are sleepy, sleep.”

The prea-’hers of the new gospel say that the ability to take a nap at will

is the secret of some men’s success. Benjamin F. Butler,- of Massachusetts, it is recalled, found great refreshment in sleeping on the short railway journey to and from his office. A highly successful lawyer in a small city of the Atlantic Coast walked the better part of a mile home to his midday dinner and then took a nap that sometimes

ran to half an hour. He was good then for a long afternoon, and, if need be, a long evening at his office. The doctors do not expect New York to imitate the Southern custom of a long midday suspension of business for luncheon and the siesta, but they do expect' that tired men will gradually learn the value of the brief nap in business hours. Men who sit long alone in their offices often fight sleep for an hour or more in midmorning or after the noon-

day luncheon, and, coming out victors, stick to their work.

In that hour of struggle with sleep the man is only half himself, and the doctors say that the thing that enables him to recover the full use of his powers and keep on working effectively for the rest of the day is the fact that nature has really had her way; that for a few seconds together he has partly or wholly lost consciousness, and has spread a five or ten minute nap over an hour or perhaps an hour and a half.

It would have been money in his pocket to put his head down on the desk when sleep began to creep upon him and take a solid nap of the neces-

sary length, they declare. Such a nap, not necessarily more than five or eight minutes, possibly as little as three or four, is often followed by an astonishing refreshment that almost doubles the man's powers.—“ New York Sun.”