ELECTRICITY 



Electricity. A powerful electro-mag- 

 net used by an oculist to extract a steel 

 splinter from a workman's eye 



regulate and modify functional pro- 

 cesses such as nutrition, secretion, 

 circulation, and sleep ; and in some 

 inflammatory conditions, paralysis, 

 skin affections, consumption, and 

 cancer. For the production of 

 the " faradic " form an induction 

 coil is used, the current from the 

 secondary coil being applied to the 

 body by means of electrodes, as 

 when the galvanic form is employed. 

 Faradic electricity is used in spinal 

 and some other forms of paralysis, 

 in gout, rheumatism, muscular 

 rheumatism, and cramp, eczema, 

 constipation due to indigestion, 

 hypochondria, neurasthenia, and 

 hysteria. When applied to the abdo- 

 men or spine a flat, oval electrode 

 is used ; when it is desired to pick 

 out a particular muscle a small 

 needle-shaped electrode is em- 

 ployed ; while the current is also 

 applied directly in the stomach by 

 means of a small bean-shaped 

 electrode at the end of a wire 

 covered with india-rubber, which 

 is introduced into the stomach and 

 withdrawn when the necessary dose 

 has been given. 



Use of Electrodes 



Drugs are introduced into the 

 system through the skin by the aid of 

 special electrodes carrying at their 

 extremities a little roll of blotting 

 or absorbent paper which is satur- 

 ated with the drug to be introduced ; 

 the paper is attached to the cathode 

 or negative end of the circuit and 

 is applied to the skin where it is 

 desired to introduce the drug, the 

 other end of the circuit being 

 applied to some other portion of the 

 skin. In this way the drug is grad- 

 ually introduced into the tissues 

 just where it is required, and may 

 have more active effect than if 

 taken through the mouth or ad- 



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ministered in the ordinary hypo- 

 dermic fashion. In general debility 

 and in convalescence after illness 

 electricity may greatly aid re- 

 covery by improving nutrition, and 

 by its general tonic effect. Used 

 in health under proper control its 

 tendency is to increase muscular 

 power. 



Electricity is used also in medi- 

 cine to illuminate the interior of 

 certain parts of the body by the 

 direct introduction of minute 

 electric lamps and particularly for 

 the examination of the throat and 

 the eye ; and as a cauteriser for the 

 destruction of superfluous hairs, 

 warts, and other abnormal growths ; 

 while powerful electro-magnets are 

 employed to pull particles of iron 

 out of the eye. The X-rays, while 

 not strictly electrical, are indirectly 

 so, being a secondary product of 

 electric action, and constitute pro- 

 bably the most valuable of all the 

 contributions made by electricity 

 to medical science. 



ATMOSPHERIC ELECTRICITY. The 

 atmosphere, for a certain distance 

 above the earth, has been proved 

 to be almost continuously charged 

 with electricity. Normally the elec- 

 tricity of the air is positive and that 

 of the surface of the earth negative, 

 and if we take the average of fine 

 weather as determined by a series 

 of careful examinations carried out 

 at Kew many years ago, as repre- 

 sented by + 4 as the potential, it 

 would appear that in this country 

 the potential rarely falls to 1, 

 though now and again it may drop 

 for a moment to as low as O'l. 

 It is strong during E. and N.E. 

 winds ; in wet weather with sudden 

 heavy showers it may be as much 

 as 30 either positive or negative ; 

 during snow the strength is about 

 the same as in wet weather, but it 

 is nearly always positive. With high 

 wind ,and snow or severe frost it 

 may go to + 100 or even higher. 

 In thunder-storms it will often be 

 over 100 either positive or negative, 

 though at such times it may reach 

 200, there being usually a pre- 

 ponderance of negative electricity 

 in thunder-storms. It may change 

 instantly from positive to negative 

 or negative to positive with a flash 

 of lightning, and with only less 

 rapidity with a sudden shower of 

 rain. Even in fair weather the 

 changes may be rapid, while in 

 storms the oscillations may be so 

 frequent and violent as to keep the 

 indicating instruments in continual 

 agitation. In all regions there 

 appear to be at least one period of 

 high intensity and one of low every 

 twenty -four hours, and in some two 

 such maxima and minima periods. 

 , Apart from the normal electric 

 condition of the atmosphere and the 



ELECTRICITY 



obvious manifestation afforded by 

 thunder-storms, the Aurora offers 

 another evidence of profound elec- 

 trical disturbance in the earth's 

 atmosphere. It cannot, however, 

 be said that our knowledge of the 

 cause or causes of atmospheric elec- 

 tricity is as yet either exact or 

 complete. 



Theories of Atmospheric Electricity 

 Many plausible theories have 

 been put forward to account for the 

 phenomena : evaporation of water 

 from the surface of the earth, the 

 friction of the particles of air in the 

 wind, or of particles of water in the 

 air, the heat currents in the atmo- 

 sphere, the volumes of steam 

 emitted by volcanoes and geysers, 

 have all been suggested as causes 

 and rejected as inadequate explana- 

 tions. The fact that the ultra- 

 violet rays of the solar spectrum 

 will discharge a negatively electri- 

 fied body as if they were them- 

 selves positive, has suggested that 

 radiation from the sun may give 

 a positive charge of electricity to 

 the atmosphere which in turn 

 would induce negative at the sur- 

 face of the earth. 



A theory propounded by Sir J. 

 J. Thomson appears to offer a 

 satisfactory explanation of some 

 of the immediate phenomena of 

 atmospheric electricity. This as- 

 sumes that when the vapour of 

 water in the atmosphere first 

 condenses it does so by preference 

 on particles of dust that are nega- 

 tively electrified, and that in con- 

 sequence the first formed parts of 

 fog or cloud are heavier than those 

 formed later, and, falling first to 

 the ground, carry with them the 

 negative electricity. The theory, 

 however, does not go very far. It 

 is possible that all the suggested 

 causes to which reference has been 

 made contribute more or less to 

 the electricity of the earth's atmo- 

 sphere, but there is little doubt 

 that we must look to radiation 

 from the sun as the chief source. 



Electron Theory 



Arrhenius, the Swedish scien- 

 tist, has suggested that the sun is 

 continuously bombarding space 

 with electrons (q.v.), that the great 

 mass of those approaching the 

 earth are gathered up by the 

 magnetic forces which are concen- 

 trated about the earth's poles, 

 where, owing to the rarefied atmo- 

 sphere in those regions, they 

 become manifest in aurora, pre- 

 cisely as in a vacuum tube when a 

 discharge of electricity takes place 

 therein. Accepting this highly 

 probable theory, it is easy to sup- 

 pose that not all the electrons are 

 carried to the poles, that some 

 penetrate other portions of the 

 earth's atmosphere. And, in any 



