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Aviation History
1913
1913 - 1174.PDF
[/UGHr seaplane No. 88 left its hangar and made a dash up the harbour. The machine rose gracefully, but suddenly turned her nose seawards and dived into the water, disappearing beneath the waves. She rose again in a few seconds, but when near the mouth of the harbour the machine turned sideways and collapsed. When she struck the water there was a loud explosion and the machine disappeared. Tugs were quickly on the scene and the two officers were rescued from the wreckage. The machine was subsequently salved." To allow a machine to turn sideways after having the ® ® NOVEMBER I, 1913. skill to execute the porpoise business and come through it successfully is beyond me. What I see in the matter is money, and fine sport. I do not know exactly how this machine is built, but I can probably find out. Now, of course, you can no doubt see the wheeze, and want to take some shares. On the coast in the summer; a few porpoiseplanes ; a few pilots ; pilot and passenger in bathing costume; dive from 200; guaranteed under water flight of 100 feet; two guineas; fortune; retire ment; there you are, all through a wet Sunday and what followed. ® * THE RELATIONSHIP BETWEEN ELECTRO-OPTICS AND AVIATION.* By HENRI COANDA, Technical Director IN order to accept the following conclusions it is necessary to admit the non-existence of the infinitely small material atom, and to replace this immaterial atom by an enormous energy. It is the existence of this energy that enables us to understand how there is a direct relation between two phenomena, or how there is a relation between two tffects of energy by the intermediary of a substance that changes its state during transmission. This hypothesis, the result of the work of Ramsay and Thompson, enables us to comprehend the effects of visible and invisible sun rays on the electric state of the earth's surface while they pass through the atmosphere. Since Faraday in 1845, who communicated a paper on electro- optical phenomena to the Royal Society, until the contemporary study of Hertzian waves, the relationship between electricity and light through the intermediary of matter has been remarked and studied. I give the following abstract from Faraday's paper of 1845 to the Royal Society, on " The Action of Elements on Light, and electro- optical phenomena " (as given by Dr. Giurgea): " For a long time it has been my opinion, amounting almost to a conviction, s-hared, moreover, I believe, by many others among those who love the study of natural sciences, that the different forms in which matter manifests have a common origin ; in fine, that they are in such relationship, in such connection, that they can be con verted, so to speak, the one into the other, and that there exists in their respective actions equivalent power." Later, in the conclusion of this same law of Faraday's, we find a very interesting observation: " Magnetic force does not act on the ray of light directly, and without the intervention of matter, but through the intermediary of the substance in which they exist simultaneously with the ray. The substances and the forces transmit the one to the other, and receive, the one from the other, the ability to act on the light." Subsequently, in 1865, Maxwell wrote the electro-magnetic theory of light. The explanation of electro-magnetic phenomena is based on the wave motion of light, which supposes the existence of a medium. The electro-magnetic medium possesses identical properties to those of the medium in which light is propagated. The luminous body expends a certain quantity of energy, and if this light is absorbed by the other body, the latter grows warm. In the interval during which the light leaves the first body, but is not yet received by the second body, it exists as energy in the intermediary medium. One part of this energy is potential, the other is kinetic, as is proved by the research of Huygens, Fresnel, Young, Green, &c. The potential energy is due to the deformation of the elementary particles of the medium, which brings with it the following con clusion :—The medium must be regarded as elastic. As the kinetic energy is due to a vibratory movement, the medium must have a finite density. We can thus determine this energy in two forms : electro-static and electro-kinetic. Dr. Kerr, of Glasgow, published in the Philosophical Magazine, in 1865, an article, entitled " A New Relationship between Electricity and Light." The phenomena observed by Kerr differ from those observed by Faraday for the magnetic field. Kerr found that the dielectric sustained a deformation that rendered it doubly refracting, and the light that is depolarised will be polarised elliptically. In reference to the action of the electric field on gases, I recall the theory of Professor Lippmann on their electric contraction. Dr. Giurgea investigates the phenomenon of electric double refraction [* Translated from the French.—ED.] of the British and Colonial Aeroplane Co. discovered by Kerr, of the refractive index or electrolysed gases, and of the electric contraction of gases discovered by Dr. Boltzmann, and studied theoretically by Prof. Lippmann. These phenomena are produced simultaneously, inseparably, under the action of the same electric field. At the end of their experiments, it was well proved that gas contracts under the action of an electric field. Further, the move ment sustained by a vapour can be considered as anisotropic, for an electric field that deforms a dielectric has every chance of making it anisotropic. Following the study of these phenomena, Dr. Giurgea sought to determine the value of Kerr's constant, to demonstrate that electric double refraction of bodies is strongly influenced by a thermal double refraction of the opposite kind. This thermal double refraction is due to the infra red rays of a length of 850-910 fi/j.. At the moment of the disappearance of the electric double refraction, it remains as hysteresis in the matter. Its value is greater according as the duration is longer. It has been remarked that the production of thermal double refraction does not correspond to a general rise in temperature, but to a local rise of temperature following the lines of force. During the production of the electric field, and during the whole period of the electric action, considerable mechanical disturbance of the matter is produced, and violent eddies are formed. We are now in a position to comprehend the movements of aerial currents independently of the increase in the density of the atmosphere, and dependent above all on the dielectric constant of different gaseous mixtures or vapour. The electric potential of the atmosphere varies under the electro-optic influence of visible and invisible rays from the sun, and under the electro-static action of clouds. It is especially to be emphasised that asymmetry caused in any medium by energy is opposed by a deformation of matter. Solar light, visible or invisible, is the agent that emits the lines ot force from the sun, and there are also vibrations of matter. Lines of force emitted from a body depend on its nature, and their direction is largely governed by its form. The lines of force at the surface of the earth are thus governed by the nature of the surface and the sub-soil. Water is the most active of all bodies, equally so if the stream is subterranean. The lines of force emitted by the water are attracted by the solar rays. This atmospheric electric potential in the neighbourhood of the earth depends solely on the local meteorological state above mentioned. This tension depends also on the nature of the earth and sub-soil, and the electricity accumulates for preference on the water courses, subterranean pools, and metalliferous strata, and it is this nature of soil and sub-soil that determines in an exact manner the electric state of the atmosphere at the earth's surface. By following the variations of this surface electric potential, one can map out the nature of the soil and sub-soil, provided that due allowance be made for the influence of the sun's rays, and for the electro-static effects of clouds. At a given point in the atmosphere near the earth, the same variation of electric potential will always be produced by the same meteorological conditions. It is, above all, the ultra violet rays below 252 pp in length that affect the lines of force for the soil and sub-soil. These rays are absorbed by the air, which explains why variations of electric potential in the atmosphere are felt when the luminous rays traverse a less thick layer of air. This is the case when the ray is nearly vertical. Other factors may also influence matters—for example, ozone, which has a greater affinity for these rays. When an aircraft moves with a certain speed, it. becomes by friction against the air a very sensible electroscope. 1200
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