NA TURE 



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THURSDAY, MAY 23, 1895. 



WERNER VON SIEMENS. 

 The Scientific and Technical Papers of Werner von 

 Siemens. Translated from the second (ierman edition. 

 Two volumes. (London : John Murray, 1892 and 

 1895.) 



THESE two large volumes form a complete history of 

 the work of Werner Siemens, and give a \er)' vivid 

 impression of his unceasing activity. In addition to build- 

 ing up one of the largest commercial houses on the con- 

 tinent, and by his inventions and discoveries materially 

 assisting in almost every step which, during the last fifty 

 years, has been made in the application of electricity to 

 the service of man, he has found time to conduct long 

 researches on subjects unconnected with his technical 

 work, and, particular y in his later years, has written 

 several important papers on meteorology. It is chiefly, 

 however, in connection with electro-technology that the 

 name of Siemens is famous, for it is this subject that 

 Werner Siemens in Germany, and Sir William Siemens in 

 England, have made particularly their own. 



The first of the volumes under notice contains the 

 " scientific " papers, while the second contains the tech- 

 nical ones ; the papers in either volume being arranged 

 in chronological order. The distinction drawn between 

 the scientific and technical papers is more apparent than 

 real, for in most of the papers included under the first of 

 these heads it is very evident that the investigations were 

 suggested by some difficulty met with in practice, or were 

 undertaken with a view to some practical application. 

 Hence it is questionable whether it would not have been 

 better to keep all the papers together, arranging them in 

 chronological order, so as to render the relation between 

 the experimental or theoretical investigation and its prac- 

 tical application more obvious. 



The first paper in chronological order is a note on " an 

 application by Second-Lieutenant Werner Siemens for a 

 patent for a process of dissolving gold by means of the 

 galvanic current, and for gilding by the wet method." 

 Although no complete account is given of the method 

 employed, this note is of interest for two reasons. In the 

 first place, the experiments which led to the discovery of 

 this method of electro-gilding were made in a cell at the 

 citadel of Magdeburg, in which place, on account of his 

 participation in a duel, young Siemens was at the time a 

 prisoner ; the chemicals and apparatus employed being 

 procured and smuggled into the fortress by a friendly 

 chemist of the town. In the second place, it was the sale 

 of the patent rights in this invention in England which 

 supplied the brothers Werner and William with the 

 necessar)' funds to carry on their experiments, and so 

 helped to lay the foundation of the important firms of 

 Siemens and Halske in Ciermany, and Siemens Bros, in 

 England. 



Although still in the army, Werner Siemens continued 

 his scientific experiments, the next discovery of im- 

 portance having reference to the insulation of electric 

 wires with gutta-percha. When the newly-discovered 

 substance, gutta-percha, was first put upon the English 

 market, William Siemens sent a specimen to his brother, 

 NO. 1334, VOL. 52] 



who, being at that time engaged in an attempt to discover 

 a practicable method of insulating underground telegraph 

 wires, immediately proceeded to tr\- if this substance was 

 suitable for the purpose, and found that even a thin layer 

 when freed from moisture possessed sufficient insulating 

 power. In addition, the property which gutta-percha 

 possesses of becoming plastic and sticking together when 

 heated, appeared to remove the difficulty of making sound 

 joints between the separate pieces of the covering. At 

 first a hot gutta-percha strip was pressed round the wire 

 by means of grooved rollers, and cables insulated in this 

 way were used on a short underground telegraph line 

 between Berlin and C.ross-Heeren. as well as for the sub- 

 marine mines, the first of their kind, which Siemens laid 

 down for the defence of Kiel harbour. It was found, 

 howe\er, that the method of covering was defecti\e, since 

 the material rolled round the wire often did not stick well 

 together. In order to overcome this difficulty, Siemens, 

 in conjunction with his future partner, Halske, invented a 

 machine by means of which gutta-percha could be con- 

 tinuously pressed round the wire without any seam. The 

 plastic gutta-percha is in this machine forced into a 

 metal box having a number of holes drilled through two 

 opposite sides ; the holes on the lower side being of such 

 a size as to just allow the passage of the uncovered wire, 

 while the holes on the upper side are the size of the 

 finished insulated wire. The wires pass through the lower 

 narrow holes into the space filled with hot gutta-percha, 

 and come out through the upper holes covered with a 

 uniform and seamless coating. 



In consequence of the perfection with which wires 

 could be insulated by this new method, Siemens was 

 employed in designing and laying the Prussian State 

 telegraphs, and in this connection devised a method for 

 testing the perfection of the insulation during the manu- 

 facture of the cable, and also a system of tests for localis- 

 ing the position of any " faults " which might occur after 

 the cable was buried in the ground. While superintend- 

 ing the laying of the Red Sea cable, these systematic 

 tests were further elaborated by Siemens, and the success 

 which attended the laying of this cable, as well as the 

 numerous others laid by his firm, may be traced in a 

 great measure to the severe and continuous testing to 

 which the cables were subjected during the process of 

 manufacture and the subsequent laying. 



In practically all the earlier telegraph lines of the 

 Prussian telegraphs, underground conductors w^ere em- 

 ployed, since Siemens considered they were better than 

 overhead cdnductors, being less liable to malicious or 

 accidental injury. In addition, they are unaflfccted by 

 the atmospheric electricity, which in a dry climate often 

 renders the overhead lines unworkable. .Although these 

 underground lines were in after years a source of con- 

 stant trouble, on account of the frequent break-downs, 

 attributed by Siemens to careless and defective repairing, 

 yet their use led him to two ver>' interesting discoveries. 

 in the first place, he found that an underground cable 

 acted like a large Leyden jar, the copper conductor form- 

 ing the inside, and the moist earth the outside coating. 

 On this account, it was found necessary to design special 

 apparatus to work satisfactorily through these -under- 

 ground lines, and the practice obtained in designing such 

 instruments must have stood him in good stead when he 



