22 



SCIENCE. 



[Vol. XII. No. 284- 



proportional to their absolute temperature ; that is to say, if the 

 temperature of a metal could be reduced to absolute zero, its re- 

 sistance would be annihilated, and its conductivity increase to in- 

 finity. M. Wroblewski took advantage of one of the new methods 

 of producing intense cold ; namely, that by means of boiling nitro- 

 gen at the temperature of its solidification. Wires of copper about 

 XffTT of a millimetre in diameter, covered with a double layer of silk, 

 were taken, their conductivity being guaranteed by the makers at 

 ninety-eight per cent of that of pure copper. With this wire M. 

 Wroblewski wound small bobbins having a resistance at ordinary 

 temperatures of about 3 and 20 Siemens units. As the bobbin had 

 to be plunged in liquefied gas, M. Wroblewski began his investiga- 

 tion by studying the electric properties of liquid oxygen and nitro- 

 gen. He found that these substances ought to be ranked among 

 the most perfect insulators. The resistances of the bobbins were 

 then measured by the Wheatstone-Kirchhoff method at the tem- 

 perature of boiling water, ordinary temperature, the temperature of 

 melting ice, the temperature of boiling ethylene at atmospheric 

 pressure ( — I03°C.), the critical temperature of nitrogen ( — I46''C.), 

 the temperature of boiling nitrogen under atmospheric pressure 

 ( — 193° C), and a temperature nearly that of the solidification of 

 nitrogen (— 2og°C. to — 202°C.). The results are embodied in the 

 following table, where t is the temperature, r the resistance in 

 Siemens units, and a the co-efficient of variation of resistance be- 

 tween two consecutive temperatures : — 



These numbers seem to show that the resistance decreases much 

 more quickly than the absolute temperature of the specimens, and 

 approaches nil sX a temperature not very far from that obtained by 

 evaporating liquid nitrogen in a vacuum. 



Underground Electric-Light Wires.— Several deaths 

 caused by shocks from electric-light wires have called attention to 

 the dangers of the present systems of high-potential distribution, 

 and much has been written in the daily journals about the deadly 

 electric-light wires. The general remedy proposed is to put the 

 wires underground, and in many cities ordinances have been passed 

 directing that all wires shall be buried within a certain time. In 

 the present state of things it will be impossible to obey these or- 

 dinances. There are great difficulties and expenses incident to any 

 general system of underground distribution in our large cities. The 

 enormous number of telephone and telegraph lines that must be 

 put in conduits with the electric-light wires — for the scheme em- 

 braces the burying of all wires — introduces the factor of disturb- 

 ance of messages from induction as well as the great difficulty of 

 preventing leakage between the different lines, and from the lines 

 to the ground. And in New York, where this work is being done 

 on a large scale, the commission which directs it is composed of 

 politicians who have no idea of the mechanical and electrical dif- 

 ficulties that must be met and overcome. Again : it is very much 

 a question whether the putting of arc-light wires under ground will 

 decrease the danger. The wires have still to be taken to the lamps, 

 and in the branch wires there is the same possibility of accident as 

 before. As the case now stands, then, the putting of electric wires 

 under ground will be attended with trouble and expense, possibly 

 with failure. It will not greatly decrease the danger of high-po- 

 tential lighting, and it will greatly retard its development. At the 

 same time an efficient underground system is much to be desired. 

 It would be as foolish to give up all attempts in this direction as to 

 try to accomplish it at once, without the necessary experience. 



The best way would seem to be a gradual putting of the wires 

 under ground, instead of a city directing all the wires to be placed 

 under ground by a certain time. Let them order a certain per 

 cent each year, the localities to be determined by people who know 

 something about the subject. In this way experience will be gained 

 in the cheapest manner, and, if it is found practicable, the end will 

 finally be reached without injury to the companies concerned. 



NOTES AND NEWS. 



The AtkencBuin of June 30 announces the death at Brighton 

 of Mr. Edmund Gurney. jVIr. Gurney had been subject to obsti- 

 nate sleeplessness, and had had recourse to opiates. It was an- 

 overdose of chloroform that led to his accidental death. Mr. Gur- 

 ney 's best known work was his ' Power of Sound,' a very excellent, 

 treatise, and one of permanent value. Of late years he has been 

 oftenest before the public by his contributions to the Proceedings 

 of the Psychic Research Society, of which he was the honorary sec- 

 retary. He was the chief author of the ' Phantasms of the Living,' 

 and the man to whom, more than to any one else, is due the great 

 interest in psychic studies which this society has aroused. Mr. 

 Gurney had committed himself to the telepathic hypothesis, and 

 was busy to the last in developing that theory. However much one 

 may differ from him in his views regarding the problems of psychic 

 research, all must acknowledge to a great admiration for the cour- 

 age and industry of the scientist venturing boldly into this psychic 

 ' lieart of Africa,' and reporting patiently and systematically his ad- 

 ventures in that mysterious region. His loss is a very serious one 

 to the cause to which he had devoted so many years of his life. 



— A. C. McClurg & Co. have just issued the first two volumes of 

 the proposed series of The Great French Writers. The publica- 

 tion of this series has been delayed by the fact that the publishers 

 were disappointed with the translations brought out in England, 

 and therefore undertook the expense of entirely new translations. 



A careful and very valuable bibliography of the works of Sir 



Isaac Newton, with a list of books illustrating his life and works, by 

 G. J. Gray, has just been issued by Messrs. Macmillan and Bowes, 

 Cambridge. The bibliography is divided into ten sections : (l) 

 collected editions of works ; (2) the ' Principia ; ' (3) 'Optics;' (4) 

 ' Fluxions ; ' (5) ' Arithmetica Universalis ; ' (5) minor works ; (7) 

 theological and miscellaneous works ; (8) works edited by Newton ; 

 (9) memoirs, etc.; (10) index. A new edition of the late Pro- 

 fessor Humpidge's translation of Dr. Hermann Kolbe's 'Short 

 Text-Book of Inorganic Chemistry' (Longman's) has been issued. 

 The greater part of this edition was prepared by Dr. Humpidge last 

 summer. Being unable, owing to failing health, to complete the- 

 task of revision, he asked Prof. D. E. Jones of the University Col- 

 lege, Aberystwith, to undertake it, and to see the book through the 



press. Mr. Leland will shortly send to the printer his work on 



' Americanisms,' which will follow on the ' Dictionary of Slang, 

 Jargon, and Cant,' now in the press. It will contain much folk- 

 lore in the form of proverbs, songs, and popular phrases, and also the 

 etymology and history of the words, as far as they could be traced. 

 The work will include an account of American dialects, su^ch as 



Pennsylvanian Dutch, Chinook, Creole, and Gumbo. Nearly the 



whole edition of Mr. George Seilhamer's ' History of the American 

 Theatre: Before the Revolution,' has been placed ; a second vol- 

 ume, ' During the Revolution and After,' is in press, and will be 

 ready in the autumn. Both volumes are published through the 



Globe Printing-House, Philadelphia. Kegan Paul, Trench, & 



Co. have made arrangements for the publication of a set of half- 

 crown books to be entitled ' English Actors : Ten Biographies.' 

 The series will be under the general editorship of Mr. William 

 Archer, and will include lives of Betterton, Cibber, Macklin, Gar- 

 rick, the Dibdins, the Kembles, EUiston, the Keans, the Matthews, 

 and Macready. Mr. Joseph Knight will deal with Garrick, Mr. R. 

 W. Lowe with Betterton, Mr. E. R. Dibdin with the author of 

 ' Tom Bowling,' and the editor himself with the Keans. The sub- 

 jects have been selected so as to cover as completely as possible 

 the whole field of English acting from the Restoration to our own 

 time. Mr. W. J. Linton, one of the leading authorities on wood- 

 engravings of the day, has issued a prospectus, with specimert. 



