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SCIENTIFIC AMERICAN            Jan., 1912           399

away from the transverse bulkheads for any great distance. 

The purpose of this article, after having discussed the primary forces and effects, is to discuss the secondary forces within the ship itself, and to see if it were not these which led to the destruction of the ship.

Let us first consider the boilers and engines. These were undoubtedly very securely fastened, but their weight amounts to several hundred tons, and their momentum if the ship was suddenly stopped must be sufficient to tear them from their fastenings, break all the steam pipes, and hurl them with great force against, and probably destroying, all of the adjoining bulkheads; this alone would scald everyone in the hold instantly and fill the ship with suffocating steam and gases.

Second:  There were several thousand tons of freight and coal stored against the bulkheads whose momentum must have been like an avalanche, sweeping away the bulkheads as though they were paper, so that the water which entered through the destroyed bow could reach every part of the ship without hinderance.                            ERNEST C. MOORE.
  New York City.

              THE PERIL OF THE WIRELESS MEDDLER
To the Editor of the SCIENTIFIC AMERICAN:

In the April 13th issue of the SCIENTIFIC AMERICAN, a correspondent-Edwin L. Powell-make an untimely and futile defense of the amateur who interferes with the transmission of official wireless messages. Untimely; in view of the fact that forty-eight hours the Siasconset station on Nantucket Island was prevented from receiving wireless messages from the "Carpathia" when she was hurrying to New York with the survivors of the terrible "Titanic" disaster. Futile when one considers the efficiency of the Governments apparatus located at every important point along the Atlantic seaboard.

It is a deplorable condition when news of vital import such as this, involving the lives of two thousand passengers in mid-ocean, is confused, and the lives of those passengers jeopardized by irresponsible meddlers. This class of wireless experimenters, while they may not willfully interfere with official dispatches, nevertheless do interfere, which fact is attested to by the Navy Department records and by the French Government in 1908, when "leakage" of important official messages from Eiffel Tower to the commander of French forces at Casablanca was discovered.

A French scientist pointed out the ease with which these dispatches were intercepted by an ordinary wireless apparatus of his own construction, and it was later proved that these messages were received at the French military wireless station of Verdun, and probably at a neighboring German station across th Vosges. This naturally created widespread consternation in French military circles, and steps were taken to perfect a system proof against leakage, but no system can as yet be devised to remedy this grave defect. The few instances where amateurs have assisted authorized Government operators are outweighed by the annoyance Government operators are outweighed by the annoyance occasioned by their meddling with dispatches of vital importance.

It is the amateurs who dabble in wireless and retard the progress of this branch of electrical science, and it is high time that the Government called a halt to the ever-increasing danger of amateur experimenters, and a hopeful note is sounded in the assembling on April 16th of the Cabinet by President Taft to discuss a regulation of interference from such a source. The insinuation of the above writer that the Government is to blame for "their inability to cope with interference on account of employing instruments that are antiquated and unfit for their present needs," is false and groundless.

The equipment of the Government wireless stations is of the most advanced and delicate type, but even then it would be subject to the interfering ether pulsations emanating from amateur apparatus. A rule that would be effective must not single out exceptions among the amateurs here and there, but must include them all, and this elimination of undesirable meddling certainly would not "place a strong hindrance on the advancement of the art," but on the contrary, would prove of incalculable benefit to wireless telegraphy.

I trust that this point of view, considering the wireless meddler as a peril to the lives of passengers on sinking ocean liners, is worthy of meriting a place in your valuable journal. It is certainly more practical than the idea that the amateur meddlers render a great service to the authorized stations, which is very difficult to see the light of recent developments in eastern New England.  DONALD P. BEARD.
Independence, Mo.

Starting and Alighting in an Aeroplane
To the Editor of the SCIENTIFIC AMERICAN:
Owing to repeated inquiries by the public as to the proper way of starting and alighting in an aeroplane with relation to the direction of the wind, I give an explanation through the columns of your paper.

In an aeroplane, two velocities are considered, the one which is relative to the ground and the other which is relative to the air. By velocity of the aeroplane relative to the ground is meant the distance the machine traverses in the air per unit of time, while its velocity relative to the air is the number of quare feet of air the plane passes over per unit of time.

When an aeroplane travels against the wind, it's velocity relative to the ground decreases to the extent of the velocity of the wind, and its velocity relative to the air at certain times increases temporarily to the extent of the wind's velocity. For example: If the normal velocity of the aeroplane is 40 miles an hour, and it runs against a 10-mile wind, its velocity relative to the ground would be (40 - 10), or 30 miles, while its velocity relative to the air would be (40 + 10), or 50 miles. The latter means that the plane would have, at the particular time, just as much lift as if the machine were running at the rate of 50 miles an hour in still wind.

It is the opposite when the machine runs with the wind. In this case, the velocity of the aeroplane relative to the ground increases to the extent of the velocity of the wind, and its velocity relative to the air at certain times decreases momentarily to the extent of the velocity of the wind. For example: If the normal velocity of the aeroplane is 40 miles an hour, and it runs in the direction of a 10-mile wind, its velocity relative to the ground would be (40 + 10), or 50 miles, adn its velocity relative to the air would be (40-10), or 30 miles. This means that the machine would have as much lift in the particular case as if it were traveling at the rate of 30 miles an hour in still air.

The above statement is true at the time of the change of the lateral direction of flight with relation to the direction of the wind, and also, at times of sudden changes in the velocity of the wind, which reasons give us the idea of having almost the same principle applied to the change of the longitudinal direction, the effect of which causes the difference in starting and alighting the machine relative to the air remains always the same, irrespective to the increased or decreased velocity relative to the ground, caused by the effect of the wind's velocity.

Therefore, in starting against the wind, the increased velocity relative to the air gives the aeroplane a greater lift, causing it to leave the ground within a shorter distance, and to rise in the air quicker than it would in starting with the wind, in which case the lift of the plane decreases with its decreased velocity relative to the air. For such reasons as herein mentioned, it can readily be seen that in some cases it is impossible for the machine to leave the ground in starting with the wind.

In alighting against the wind, the wind acts as a brake on the plane through the increased upward pressure, and a safe landing is certain to be had if properly made; but in alighting with the wind, the machine comes down with accelerated speed due to the decreased upward pressure, making landing very difficult even to the most skillful aviator, and in some cases the control of the machine may be lost, causing a disaster. Also, under certain conditions, whether in starting or alighting with the wind, the tail is liable to get caught by the wind turning the machine somersault.

Starting or alighting sidewise to the wind is dangerous because when the wind strikes the machine on either side of the plane, it may tilt while too near the ground, and there may be a chance of righting it up before it touches the ground, which results in a wreck.

From the foregoing, it follows that starting or alighting in an aeroplane, is preferably made against the wind.
New York city.  S. S. JERWAN, Aviator.

Gyroscopic Action in Aeroplanes
To the Editor of the SCIENTIFIC AMERICAN:
S. S. Jerwan, Joseph A. Blondin and others are debating on the natural "Gyroscopic Action in Aeroplanes." I am in the audience, so it would be very improper for me to speak to one of the debaters, but, of course, this is proper: I whisper to my neighbor, the Editor of the SCIENTIFIC AMERICAN, that nose gentlemen do not seem to be talking about the same kind of a machine.

From Mr. Jerwan's article I take it that his propeller is at the rear end of the machine. The words which Mr. Blondin quotes from "Vehicles of the Air" are probably spoken of an aeroplane with its propeller forward> I cannot speak this with certainty, for I have not had access to the book, but the idea seems quite reasonable to me.

Now, it will be readily seen that this gyroscopic action will be exactly opposite in two aeroplanes, one having the propeller at the rear and one having it forward, provided that the propellers of each are revolved in the same direction; that is, observing each from the rear, they might both revolve clockwise.
Platte, S. D.  GUY M. NASH.

Transcription Notes:
Jan., 1912 is written. The third paragraph has a double space between second and there