246 



SCIENTIFIC NEWS. 



[Sept. 7, if 



or condemn that which they do not understand. The Church itself 

 set its face against Franklin's " impious " theories, and he was laughed 

 to scorn by Europe's scientific sons ; and even now, though com- 

 missions composed of the ablest men of the land have sat and 

 reported on Franklin's work in England, France, and nearly every 

 civilised nation, the public generally remains not only ignorant of 

 the use of lightning conductors, but absolutely indifferent to their 

 erection, and, if erected, certainly careless of their proper main- 

 tenance. I found in a church not very far from here the conductor 

 leaded into a tombstone, and in a neighbouring cathedral the con- 

 ductor only a few inches in the ground, so that I could draw it out 

 with my hand. Although I called the attention of the proper 

 authorities to the absolute danger of the state of affairs, they 

 remained in the same condition for years. 



Wren's beautiful steeple in Fleet-street, St. Bride's, was well- 

 nigh destroyed by lightning in 1764. A lightning rod was fixed, 

 but so imperfectly that it was again struck. In July last (1887) it 

 was damaged because the conductor had been neglected, and had 

 lost its efficiency. 



As long as points remain points, as long as conductors remain 

 conductors, as long as the rods make proper connection with the 

 earth, lightning protectors will protect ; but if points are allowed 

 to be fused, or to corrode away ; as long as bad joints or faulty con- 

 nections are allowed to remain ; as long as bad earths, or no earths 

 exist, so long will protectors cease to protect ; and they will become 

 absolute sources of danger. Lightning conductors, if properly 

 erected, duly maintained, and periodically inspected, are an absolute 

 source of safety : but if erected by the village blacksmith, maintained 

 by the economical churchwarden, and never inspected at all, a loud 

 report will some day be heard, and the beautiful steeple will convert 

 the churchyard into a new geological formation. 



We have not yet acquired that mental confidence in the accuracy 

 of the laws that guide our procedure in protecting buildings from 

 the effects of atmospheric electrical discharges which characterises 

 most of the practical applications of electricity. Some of our 

 cherished principles have only very recently received a rough 

 shaking from the lips of Professor Oliver Lodge, F.R.S., who, how- 

 ever, has supported his brilliant experiments by rather fanciful 

 speculation, and whose revolutionary conclusions are scarcely the 

 logical deduction from his novel premises. The whole subject is 

 going to be thoroughly discussed at this meeting. 



We are now obtaining much valuable information about the nature 

 of lightning from photography. We learn that it does not, as a 

 rule, take that zigzag course conventionally used to represent a flash 

 on canvas. Its course is much more erratic and sinuous, its con- 

 struction more complicated, and pictures have been obtained of dark 

 flashes whose raison d'etre has not yet been satisfactorily accounted 

 for. The network of telegraph wires all over the country is pecu- 

 liarly subject to the effects of atmospheric electricity, but we have 

 completely mastered the vagaries of lightning discharges in our 

 apparatus and cables. Accidents are now very few and far between. 



The art of transmitting intelligence to a distance beyond the reach 

 of the ear and the eye, by the instantaneous effects of electricity, 

 had been the dream of the philosopher for nearly a century, when 

 in 1837 it was rendered a practical success by the commercial and 

 far-sighted energy of Cooke, and the scientific knowledge and 

 inventive genius of Wheatstone. The metallic arc of Galvani (1790) 

 and the developments of Volta (1796) had been so far improved 

 that currents could be generated of any strength, the law of Ohm 

 (1828) had shown how they could be transmitted to any distances, 

 the deflection of the magnetic needle by Oersted in 1819, and the 

 formation of an electro-magnet by Ampere and Sturgeon, and 

 the attraction of its armature had indicated how those currents could 

 be rendered visible as well as audible. 



Cooke and Wheatstone, in 1837, utilised the deflection of the 

 needle to the right and the left to form an alphabet. Morse used 

 the attraction of the armature of an electro-magnet to raise a metal 

 style to impress or emboss moving paper with visible dots and dashes. 

 Steinheil imprinted dots in ink on the different sides of a line on 

 paper, and also struck two bells of different sound to affect the ear. 

 Breguet reproduced in miniature the actual movements of the 

 semaphore then so much in use in France ; while others rendered 

 practical the favourite idea of moving an indicator around a dial, on 

 which the alphabet and the numerals were printed, and causing it to 

 dwell against the symbol to be read— the A, B, C instrument of 

 Wheatstone in England, and of Siemens in Germany. Wheatstone 

 conceived the notion of printing the actual letters of the alphabet 

 in bold Roman type on paper — a plan which was made a perfect 

 success by Hughes in 1854. 



At the present moment the needle system of Cooke and Wheat- 

 stone, as well as the A, B, C dial telegraph, are very largely used 

 in England on our railways and in our smaller post-offices. The 

 Morse recorder and the Hughes type-printer are universally used on 



the continent ; while in America the dot and dash alphabet of Morse 

 is impressed on the consciousness through the ear by the sound of 

 the moving armature striking against the stops that limit its motion. 

 In our larger and busier offices the Morse sounder and the bell 

 system, as perfected by Bright, are very largely used, while the press 

 of this country is supplied with news which is recorded on paper by 

 ink dots and dashes at a speed that is almost fabulous. 



Sir William Thomson's mirror— the most delicate form of the 

 needle system — where the vibratory motions of an imponderable 

 ray of light convey words to the reader, and his recorder, where the 

 wavy motion of a line of ink spirted on paper by the frictionless 

 repulsion of electricity performs the same function, are exclusively 

 employed on our long submarine cables. 



Bakewell in 1848 showed haw it was possible to reproduce fac- 

 similes of handwriting and of drawing at a distance, and in 1879 

 E. A. Cowper reproduced one's own handwriting, the moving pen 

 at one station so controlling the currents flowing on the line wire 

 that they caused a similar pen to make similar motions at the other 

 distant station. Neither of these plans, the former beautifully 

 developed by Caselli and d'Arlincourt, and the latter improved by 

 Robertson and Elisha Gray, have yet reached the practical 

 stage. 



The perfection of telegraphy has been attained by that chief 

 marvel of this electrical age — the speaking telephone of Graham 

 Bell. The reproduction of the human voice at a distance, restricted 

 only by geographical limits, seems to have reached the confines of 

 human ingenuity ; and though wild enthusiasts have dreamt of re- 

 producing objects abroad visible to the naked eye at home, no one 

 at the present moment can say that such a thing is possible, while in 

 face of the wonders that have been done no one dare say that it is 

 impossible. 



At the meeting of the Association in Plymouth in 1877, I was 

 able for the first time in this country to show the telephone at work. 

 Since then its use has advanced with giant strides. There are pro- 

 bably a million instruments at work now throughout the civilised 

 world. Its development has been regularly chronicled at our meet- 

 ings. As far as the receiving part of the apparatus is concerned, it 

 remains precisely the same as that which I brought over from 

 America in 1877 > Du t the transmitter, ever since the discovery of 

 the microphone by Hughes in 1878, has been entirely remodelled. 

 Edison's carbon transmitter was a great step in advance ; but the 

 modern transmitters of Moseley, Berliner, D'Arsonval, De Jongh, 

 leave little to be desired. The disturbances due to induction have 

 been entirely eliminated, and the laws regulating the distance to 

 which speech is possible are so well known that the specification of 

 the circuit required to connect the Land's End with John O'Groat's 

 by telephone is a simple question of calculation. A circuit has been 

 erected between Paris and Marseilles, 600 miles apart, with two 

 copper wires of 6£ gauge, weighing 540 lbs. per mile, and conversa- 

 tion is easily maintained between those important cities at the cost 

 of three francs for three minutes. One scarcely knows which fact is 

 the more astounding — the distance at which the human voice can be 

 reproduced, or the ridiculously simple apparatus that performs the 

 reproduction. But more marvellous than either is the extreme sen- 

 sitiveness of the instrument itself, for the energy contained in one 

 heat unit (gramme- water-degree) would, according to Pellat, main- 

 tain a continuous sound for 10,000 years. 



The influence which electric currents exert on neighbouring wires 

 extends to enormous distances, and communication between trains, 

 and ships in motion, between armies inside and outside besieged 

 cities, between islands and the mainland, has become possible 

 without the aid of wires at all, by the induction which is exerted 

 through space itself. On the Lehigh Valley Railway, in the United 

 States, such a system of telegraphing without wires is in actual 

 daily use. 



Electric lighting has become popular, not alone from the beauty 

 of the light itself, but from its great hygienic qualities in maintain- 

 ing the purity and coolness of the air we breathe. The electric light 

 need not be more brilliant than gas, but it must be more healthy. It 

 need not be cooler than a wax candle, but it must be brighter, 

 steadier, and more pleasant to the eye. In fact, it can be rendered 

 the most perfect artificial illuminant at our disposal, for it can illu- 

 mine a room without being seen directly by the eye ; it can be made 

 absolutely steady and uniform without irritating the retina ; it does 

 not poison the air by carbonic acid and carbonic oxide, or dirty the 

 decorations by depositing unconsumed carbon ; it does not destroy 

 books or articles of vertu and art by forming water which absorbs 

 sulphur acids ; and it does not unnecessarily heat the room. 



The production of light by any means implies the consumption of 

 energy, and this can be measured in watts, or the rate at which 

 this energy is consumed. A watt is jja part of a horse-power. It 

 is a very convenient and sensible unit of power, and will in time re- 

 place the meaningless horse-power. 



