EFFECT OF WATER ON FISH

IT

T has long been admitted by biologists that various forms of life are modified by the medium in which they exist.

M. Houssay, a learned professor at the Sorbonne, Paris, has recently been studying the exact action of the exterior medium upon fish. The examination of a fish shows a body the anterior large, tapering at the posterior, horizontally flat at the front and vertically flattened at the rear. From this body grow out pairs of pectoral and abdominal fins, and single dorsal, caudal and anal fins. The various forms of fish make the subject quite a difficult study.

The phenomenon of modeling is shown by filling a long rubber bag with a plastic liquidad closing it with a stopper. The bag moving in the water, the stopper at the front, takes the form of an inverted vein. It becomes flattened at the front in a horizontal plane, and in the rear a vertical plane. We must also attribute to the modeling action of the water, the origin of the fins. For, at a certain speed the form of inverted vein. has been extended on the edges by the stretching of two thin strips, the one anterior in the horizontal plane, the other posterior in the vertical plane. The resistance of the water during the progress has defined these two strips to a certain number of lobes-the fins. The fins, due to the moulding by the water, are on their side, able to react on the water.

The cetacea furnish also cases of adaptation to the liquid medium. The water has pressed and moulded them, but the adaptation has been less perfect in consequence of the former existence of a rigid skeleton, so their stability is not as good; their bodies have a tendency to turn over, which is corrected by their palette arms, and their caudal and dorsal fins which command the muscular contractions.

If the form of a fish is the necessary result of the pressure due to the resistance of water on a body relatively plastic which moves at a certain speed, the effects of moulding must continue until the resistance is minimum.

Measuring the resistance of advancement in the water has been proved by

using a number of models having the same transversal diameter as the fish. These wooden models were ballasted so as to float with the center of gravity in the ventral part. The dimensions of the models and the speed given them were in every way similar to the fish. The fins for these models were made of strips of aluminum. M. Houssay has measured by more than three hundred registering cylinder graphics the power of natural fish.

By these experiments it was

learned that all forms of fish are absolutely stable at any speed with the aid of fins. The pectoral fins of the carp are used as oars when moving slowly, but in rapid. swimming they are held close to the body. The gold fish swim with their pectorals spread horizontally when moving slowly.

As it has been proved that all forms of fish are absolutely stable, at

any speed, with the aid of fins, it suggests the idea that

the dirigible balloon might be perfected if furnished with fins which would prevent the terrible pitching at the front and back caused by the force of winds.

Attempts in the past, however, to model inventions upon the lines of Nature's creatures do not seem to have been met with

HUGE DERRICK

WHAT is declared to be the largest

and most powerful boom derrick ever set up in this country, was recently installed on Millstone Hill, Barre, Vermont where there are some very extensive quarries of granite stone of excellent grade.

The work was of unusual interest by reason not only of the size of the big stick, but on account of the methods of erection necessitated by the hillside site-methods of setting, used, so it is declared, for the first time in this country. The foundation of the derrick is set below the level of the ledge of granite, and the mast had to be raised to its place by means of a breast derrick of long-leaf pine, sixty seven feet high. This was set immediately over the site of the great mast, and braced with an elaborate network of steel cable. Another network of steel cable was lashed to the big pole about twothirds of the way. to the top of it, and a powerful system of pulleys on the breast derrick, drew the mast slowly and surely to an upright position. The rigging included 10,500 feet of wire cable, weighing over 20,000 pounds or more than ten

BUILT LIKE
A BULLET

AROTARY aeroplane engine, "built like a bullet," is the device of a California inventor, W. G. Macomber, who has busied himself for many years with gas engine improvements. It differs from the famous Gnome rotary engine, which has its cylinders set like the spokes of a wheel, in that it is built with the seven cylinders parallel to the central shaft, thus giving it an

odd resemblance to the projectile of a huge gun. This shape offers little resistance to the air and it is a model of compactness, great power reduced to small com

eight inches in length by nineteen inches in diameter. It has a weight of about 190 pounds and it is capable of developing from fifty to sixty horse

power.

Perhaps the most remarkable feature of this engine is the elimination of the crank shaft by an entirely new mechanical movement. The stroke plate transforms a horizontal reciprocating action of the pistons into a rotary motion without any loss of power-a very valuable essential.

A brief summing up of certain striking features, not to be found in other engines, is as follows:

The production of power can be stopped, while the machine is in the air without stopping the rotating of the motor, and as this engine is a true gyroscope motor and perfectly balanced, it will remain in motion for a long period. This is still further assisted by the fanning of the propeller. At any time while the engine is thus rotating in the air, the power can be re-started by the adjustment of a lever. This exclusive feature makes it absolutely safe and reliable, as it is the only engine

-so the claim is made for it-that the aerial navigator can be absolutely sure will start

every time in mid-air.

It has a perfect centrifugal, self-contained oiling system, using only a small quantity of oil and reaching every bear

INDIAN

"HOT ROOM" THAT the mod

ern hot room employed in many hospitals and physical culture establishments for the treatment of certain ailments is not an entirely new institution seems to be borne out by a peculiar custom prevailing among

hot-houses on an old Indian camping ground, and the figure inside illustrates the position assumed by the sick Indian.

A LITTLE BROTHER OF THE AUTO

NOVELTIES in the motoring line were

quite in order this season both in this country and abroad. Many combinations of the motor cycle and motor car for the use of one or two people are being marketed with success and it seems probable that they will grow more popular because of their simplicity, low price, and low expense of maintenance.

The motor tricycle shown in the illustration is the latest production of a well known English motor manufacturer and consists of a small motor car body attached to a tricycle frame and driven by a four horse-power air cooled gasoline engine. To avoid vibration, especially devised springs are attached to the body and the rear axle and the front wheel is provided with a spring fork similar to that used on the ordinary motor cycle.

certain Indian tribes, notably the Sho- shones, of Wyoming. When one of these Indians becomes sick he builds a small dome-shaped structure of branches, about ten feet in diameter, and covers it with numerous blankets, so that only a small opening is left at one side. A number of large stones heated to a very high temperature are placed in this and finally the sick Indian crawls in, closes the opening and proceeds to bake and sweat himself until he either is cured or dies. The records do not tell what percentage of them have recovered as a result of this vigorous treatment. The accompanying photograph shows one of these deserted

Ignition is furnished by a high tension magneto and the engine is supplied with a two speed gear. It is claimed by the manufacturers that the little car will develop a speed of 35 miles. an hour on ordinary good roads.