342 



NA TURE 



\Aug. 26, 1875 



gradually has their size increased'until it culminated in the hands 

 of Brunei in the Great Eastern. 



A triumph of engineering skill in ship-building, the Great 

 Eastern has not been commercially so successful. In this, as 

 in many other engineering problems, the question is not how 

 large a thing can be made, but how large, having regard to 

 other circumstances, it is proper at. the time to make it. 



If, as regards the dimensions of steamboats, we have at pre- 

 sent somewhat overstepped the limits in the Great Eastern, 

 much still remains to be done in perfecting the form of vessels, 

 whether propelled by steam or drivt^n by the force of the wind. 

 A distinguished member of this Association, Mr. Froude, has 

 now for some years devoted himself to investigations carried on 

 with a view to ascertain the form of ves«el which will offer the 

 least resistance to the water through which it must pass. So 

 many of us in these days are called upon to make journeys by 

 sea as well as by land, that we can well appreciate the value of 

 Mr. Fronde's labours, so far as they tend to curtail the time 

 which we must spend on our ocean journeys ; and we should fdl 

 feel grateful to him if from another branch of his investigations, 

 which relates to the rolling ol ships, it should result that the 

 movement in passenger vessels could be reduced. A gallant 

 attempt in this direction has lately been made by Mr. Bessemer ; 

 whether a successful one yet remains to be proved. In any event, 

 he and those who have acted with him deserve our praise for an 

 experiment which must add to our knowledge. 



It is a question of vital importance to the steamboat that the 

 consumption of fuel should be reduced to the smallest possible 

 amount, inasmuch as each ton of fuel excludes a ton of cargo. 



As improvements in the form of the hull are effected, less 

 power — that is, less fuel— will be required to propel the vessel 

 through the water for a given distance. Great as have been the 

 improvements effected in mnrine engines to this end, much still 

 remains to be done. Wolf's compound engine, so lorg over- 

 looked, is, with some improvements, being at last applied. 

 Whereas the consumption of fuel in such vessels as the Himalaya 

 useo lobe from 5 to 6:bs. of fuel per effective horse- power, it has 

 been reduced, by working steam more expansively in vessels of a 

 later date, to 2 ibs. Yet, comparing this with the total amount 

 of energy of 2 lbs. of coal, it will be found that not a tenth part 

 of the power is obtained which that amount of coal would theo- 

 retically call into action. ^ 



We live in an age when great discoveries are made, and when 

 ihey are speedily taken advantage of if they are likely to be of 

 service to mankind. 



In former times man's inventions were frequently in advance 

 of the age, and they were laid sside to await a happier era. 

 There were in those earlier days too few persons who cared to, 

 or who could, avail themselves of the proffered boon, and there 

 was no sufficient accumulation of wealth to justify its being 

 appropriated to schemes which are always in their early stage 

 more or less speculative. 



There is no more remarkable instance of the rapid utilisation 

 of what was in the first instance regarded by most men as a 

 mere scientific idea, than the adoption and extension of the 

 electric telegraph. 



Thofe who read Odter's leter written in 1773, in which he 

 m.ade known his idea of a telegraph which would enable the 

 inhabitants of Europe to converse with the Emperor of Mogul, 

 little thought that in less than a century a conversation between 

 l)cisons at points fo far distant would be possible. Still less did 

 those who saw in the following year messages sent from one room 



' Theoretical Energy of 1 lb of Coal : — 

 The proportions of heat expended in generating saturated steam at 



212° Fahr., and at 14 7 lbs. presture per square inch, from water at 

 212° are ;— 



Units Mechanical 



of equivalent 



heat. in foot lbs. 



I. In the formation of Jteam 892"8 689,242 



II. In resisting the incumbent pressure 



of i4'7 lbs. per square inch ... 72'3 55)8i5 



965.1 745,057 



One pound of Welsh coal will theoretically evaporate 15 lbs. of water at 

 212° to steam at 212°. Therefore, the full theoretical value of the 

 combustion of 2 lbs. of Welsh coal is — 

 2 X 15 X 745,057 foot pounds, 

 or> 



i3 Zi5>£i7 horse-power, if consumed in i hour. 



60 X 33.OCO 



= II 2 horse-power. 

 As the consumption of coal per effective hor.se-power in a marine 

 iiig.ne is 2 lbs., the power obtained is to the whole theoretical power 

 as 1 is to II. 



to another by Lesage in the presence of Friedrich of Prussia, 

 realise that they had before them the germ of one of the most 

 extraordinary inventions among the many that will render this 

 century famous. 



I should weary you were I to follow the slow steps by which 

 the electric telegraph of to-day was I rought to its present state 

 of efficiency. In the present century few years have passed 

 without new workers appearing in the field ; some whose object 

 was to utilise the new-found power for the benefit of mankmd, 

 ethers — and their work was not the least important in the end — 

 whose object was to investigate magnetism and electrical pheno- 

 mena as presenting scientific problems still unsolved. Galvani, 

 Volta, Oersted, Arago, Sturgeon, and Faraday, by their labour.s, 

 helped to make known the elements which rendered it possible 

 to construct the electric telegraph. With the battery, the electric 

 coil, and the electro-magnet, the elements were complete, and it 

 only remained for Sir Charles Wheatstone and others to com- 

 bine them in a useful and practically valuable form. The inven- 

 tions of Alexander, Steinheil, and tho.se of similar nature to that 

 of Sir Charles Wheatstone, were made known at a later date in 

 the same year, which will ever be memorable in the annals of 

 telegraphy.^ 



The first useful telegraph was constructed upon the Blackwall 

 Railway in 1838, Messrs. Wheatstone's and Cooke's instruments 

 being employed. From that time to this the progress of the 

 electric telegraph has been so rapid, that at the present time, 

 including land lines and submarine cables, there are in use in 

 different parts of the world not less than 400,000 miles of 

 telegraph. 



Among the numerous inventions of late years, the automatic 

 telegraph of Mr. Alexander Bain, of Dr. Werner Siemens, and 

 of Sir Charles Wheatstone, are especially worthy of notice, 

 Mr. Ikin's machine is chif fly u.sed in the United States, that of 

 Dr. Werner Siemens in Germany. In this country the machine 

 invented by Sir Charles Vvheat^tone, to whom telegraphy owes 

 so much, is chiefly employed. By his machine, after the message 

 has been punched out in a paper ribb(m by one machine on a 

 system analogous to the dot and dash of Morse, the sequence of 

 the currents requisite to transmit the message along the wire is 

 automatically determined in a second machine by this perforated 

 ribbon. This second operation is analogous to that by which in 

 jacquard's loom the motions of the threads requisite to produce 

 the pattern is determintd by perforated cards. By Vv'heatstone's 

 mactiine errors inseparable from manual labour are avoided ; and 

 what is of even more importance in a commercial point of view, 

 the time during which the wire is occupied in the transmission 

 of a message is considerably diminished. 



By the application of these automatic systems to telegraphy, 

 the speed of transmission has been wonderfidly accelerated, being 

 equal to 200 words a minute, that is, faster than a shorthand 

 writer can transcribe ; and, in fact, words can now be passed 

 along the wires of land lines with a velocity greater than can be 

 dealt with by the human agency at either end. 



Owing partly to the retarding effects of induction and other 

 causes, the speed of transmission by long submarine cables is 

 much smaller. With the cable of 1858 only 24 words per 

 minute were got through. The average with the Atlantic cable. 

 Dr. C. W. Siemens informs me, is now seventeen words, but 

 twenty-four words per minute can be read. 



One of the most striking phenomena in telegraphy is that 

 known as the duplex system, which enables messages to be sent 

 from each end of the same wire at the same time. This simul- 

 taneous transmission from both ends of a wire was proposed in 

 the early days of telegraphy, but, owing to imperfect insulation, 

 was not then found to be practicable ; but since then telegraphic 

 wires have been better insulated, and the system is now becoming 

 of great utility, as it nearly doubles the capacity for work of 

 every wire. 



And yet within how short a period of time has all the wonder- 

 ful progress in telegraphy been achieved ! How incredulous the 

 world a few years ago would have been if then told of the mar- 

 vels which in so short a space of time were to be accomplished 

 by its agency ! 



It is not long ago— 1823— that Mr. (now Sir Francis) Ronald, 

 or-e of the early pioneers in this field of science, published a 

 description of an electric telegraph. He communicated his 

 views to Lord Melville, and that nobleman was obhging enough 

 to reply that the subject should be inquired into ; but before the 

 r.ature of Sir Francis Ronald's suggestions could be known, 



I rates of patents: Wheatstone, March i, 1837; Alexander, AprJ 22, 

 1837 ; .Steinheil, July i, 1S37 : Morse, October 1837. 



