32 



NATURE 



[May 13, 1875 



code into language, must always form a very important 

 element in the commercial value of all high-speed arrange- 

 ments, when the speed is beyond that of the public 

 requirements of the circuit, 



Alexander Bain's chemical printing telegraph, invented 

 in 1846, of which this American automatic machine is 

 only a modernised adaptation, is shown at Fig. 25. It 

 combined methods of arranging, transmitting, and re- 

 ceiving electrical telegraph communications, in which 

 mechanically- composed communications were trans- 

 mitted through electric circuits, and received by che- 

 mically prepared surfaces, both apparatus being kept 

 in motion by mechanical means, without the aid of 

 magnets. The apparatus consisted of a frame con- 

 taining a driving power by which a rotatory motion 

 was imparted to the metal drum B, placed in connection 

 with the earth by means of the contact springs E E. The 

 paper strip P p, chemically prepared by being immersed 

 in a solution of sulphuric acid and prussiate of potass to 

 receive the sequence of currents transmitted through the 

 wire from the " transmitter," is wound upon the drum A, 

 and is drawn forward over the revolving earth contact B 

 at a uniform speed by reason of the pressure of the break 

 roller M, which may, whenever the paper is not required 

 to advance, be withdrawn by the lever H working on the 

 centre R, and kept in position either way by the action of 

 the spring roller w. An insulated metallic style D, in 

 connection with the line wire /", and furnished with the 

 necessary screw adjustments a, b, c, is arranged to press 

 uniformly upon the chemically-prepared paper as it passes 

 over the earth drum B. The style D can also be removed 

 from pressing contact with the paper ribbon when re- 

 quired, as indicated by the dotted outline. When there- 

 fore the style D is passing over the surface of the prepared 

 paper, and electric currents are passed through the line 

 wire/ from the distant station, the electric circuit will be 

 completed through the paper ribbon P, and the metallic 

 drum B, with the earth E, and in the passage of the current, 

 the iron in the chemical solution is decomposed and a dark 

 blue mark becomes visible upon the paper corresponding 

 in length to the duration of the current ; so that if the 

 Jacquard ribbon at the distant station is perforated into 

 the necessary length of holes to represent the sequences 

 of dots and dashes in the Morse code, to form letters and 

 words, the chemical decomposition from the style D 

 will be an accurate replica of the distant message in the 

 "dot" and "dash" symbols. It was thus that in 1846 

 Alexander Bain, the clever and ingenious Edinburgh 

 watchmaker, originated a system of electric automatic 

 chemical Jacquard printing, which even at the present day 

 is scarcely understood, and which in all probability is left 

 to American skill to develop. Its extreme simplicity 

 and wonderful chemical sensibility speak volumes in its 

 favour, provided, as has been already observed, such 

 extreme velocities can be profitably worked in this small 

 planet of ours. 



{To be continued.) 



RECENT TRENCH MATHEMATICAL 

 PUBLICATIONS 



MCHASLES is reprinting a new edition of his cele- 

 • brated work, " Apergu Historique : " the first part 

 has been already issued. The learned geometer has made 

 no alteration in the book, which was written many years 

 ago and long before he had been led to assert frivolous 

 claims in favour of Pascal, and no allusion is made to the 

 Newton forgeries. The whole work will cost no more 

 than 20J., only one-fourth of the selling price of the old 

 edition, which has for some time been very scarce. 



There has been in France a revival of interest in the 

 subject of imaginary quantities. Thus, a translation by 

 Laisant of Bellavitis's "Calcul des Equipollences " has 



been published lately. It is regarded by Bellavitis him- 

 self as a system of quaternions in one plane, and thus is 

 somewhat analogous to the efforts made in England to 

 popularise the great Hamilton's theories. But it is only 

 a partial effort, as Bellavitis's results do not admit of 

 being generalised so as to apply to solid geometry. 



M. Hoiiel, whose name is connected with the publica- 

 tion of a series of useful tables, will very likely be more 

 successful in this respect, as he is preparing a " Theory 

 of Quaternions." 



The same mathematician has edited a reprint of a work 

 on the " Geometrical Representation of Imaginary Quan- 

 tities," orieinally published in 1806 by Argand. One of 

 his objects appears to have been to defend the rights of 

 his illustrious countryman. But they are not so disregarded 

 in England as the author seems to suppose. 



The third and concluding part of the new edition 

 of Briot and Bouquet's " Theory of Elliptic Functions " 

 has appeared. It is quite a new book, though professing 

 to be a second edition of the small octavo volume which 

 became rapidly so popular amongst mathematicians. 



M. Paul de Saint Robert has published a third and 

 concluding volume of his interesting " Memoirs," several 

 of which were published in English in the Philosophical 

 Magazine. Amongst these valuable papers, which are 

 here reprinted, we must not neglect to notice the " New 

 formulae for determining the altitude from barometric 

 observations." These formulae embody the results of the 

 observations taken by Mr. James Glaisher in some of his 

 aeronautical ascents. M. Saint Robert in this way im- 

 proves the well-known Laplace's formulas, which were 

 based only on the Ramont's observations taken in the 

 Pyrenean ranges ; and takes into account the carefully 

 observed facts which had been neglected in England. 



NOTES 



The Committee on the Loan Exhibition of Scientific Appa- 

 ratus met in the Science Schools at the South Kensington 

 Museum yesterday. It has been deteimined to postpone the 

 exhibition till March 1876, and from the strength of the Committee 

 appointed and the interest taken in the scheme by scientific 

 societies, we may expect the collection to be unique. 



It will be of interest to geologists to know that Capt. Feil- 

 den, R.A., the naturalist of the senior ship of the Arctic Ex- 

 pedition, in addition to making the observations on the birds of 

 Northern Europe, Malta, India, China, and North America, 

 which will be found scattered through the pages of the " Zoolo- 

 gist" and quoted by Prof. Newton and Messrs. Sharpe and 

 Dresser in various works, has given much attention to the 

 palseonto'ogy of many of these countries, especially to the Mio- 

 cenes of Malta and the Faroe islands, and the Mastodon beds of 

 South Carolina. By permission of Prof. Ramsay, V.P.R.S., 

 the Director- General of H.M. Geological Survey, Capt. Feilden 

 has also recently been shown the method employed in carrying 

 out geological field-work by that Survey, by one of its staff, Mr. 

 De Ranee. 



The French Academy of Sciences, at its sitting on Monday 

 last, received the report of M. Fleuriais, the head of the Transit 

 of Venus Expedition to Pekin. The observations were very satis- 

 factory indeed, the four contacts having been photographed with 

 com.plete success. The weather was very boisterous all the day 

 long, but at the four important moments the observers were 

 favoured by a total absence of clouds. They succeeded in 

 executing a map of Pekin, in spite of the obstacles placed in 

 their way by the natives. The dimensions are 8,000 metres by 

 7,000, and the length of the walls is 33 kilometres. The instru- 

 ments set up by the missionaries last century are in perfect 



