January 



1885. 



SCIENCE, 



79 



ELECTRIC LIGHTING IN THE UNITED 

 STATES. 1 



Dr. Ernst Hagen, professor of applied 

 physics in the Royal polytechnic school of 

 Dresden, visited the United States in 1884, 

 and, having carefully examined the different 

 systems of electric lighting there in vogue, pre- 

 sented a report to the directors of public build- 

 ings of Berlin. The largest portion of this 

 report is devoted to the subject of incandescent 

 lighting. A certain space is given to accumu- 

 lators, and arc-lighting is also considered. The 

 writer states in his preface that his travels have 

 deepened in him the conviction that the sub- 

 division of the electric light by means of the 

 Hefner-Alterneck differential lamp gives a 

 greater degree of steadiness than is possible 

 with the lamp of any of the American S3~stems. 



The author enters at first into a comparison 

 of the cost of electric lighting in general with 

 that of gas and other sources of light. He 

 shows that nearly ninety per cent of the energy 

 l^roduced by the ordinary gas-flame is in the 

 form of heat, leaving only about ten per cent in 

 the form of the radiations which appeal to us 

 as light. He also discusses the subject of the 

 noxious gases given off by illuminating-gas, 

 and the poisonous compound called by DuBois- 

 Reymond ' anthropotoxin,' which accompanies 

 the carbonic-acid gas, and finds much to con- 

 demn in the use of illuminating-gas, and much 

 good to expect in the further extension of the 

 incandescent svstem of electric lighting. When 

 amount of light and health are considered, the 

 incandescent system is economical : viewed 

 from the point of dollars and cents, however, 

 this cannot be proved. 



The author gives a short history of the de- 

 velopment of the clynamo-machine, and the 

 reader will find here a better summary than in 

 any similar work with which we are acquainted. 

 The use of diagrams and modest engravings, 

 instead of the full-page illustrations of man} 7 

 recent treatises, is especially refreshing and 

 comforting to one's pocket. The head is filled, 

 while the pocket is not depleted, which cannot 

 be said if one buys most treatises on electric 

 lighting. 



We learn from the chapter on the incandes- 

 cent light, that Swan and Edison came almost 

 simultaneously to the invention of the carbon- 

 filament lamp, which, indeed, had been used 

 in an imperfect way by inventors long before 

 them. Both Swan and Edison reached the 



; Die elektHsche beleuchtung :* Mit besonderer beriicksichti- 

 gung der in den Vereinigten Staaten Nord-Amerikas zu central- 

 anlagen vorwiegend verwendeten systeme. Von Dr. Ernst 

 Haoe.v. Berlin, Springer, 1884. 8+307 p., illustr. 8°. 



result of a more or less permanent incandes- 

 cent lamp in 1879. The writer closes his his- 

 tor} 7 of the incandescent lamp by a glowing 

 eulogy of the man who had the genius to create 

 a new industry which employs hundreds of 

 workmen, and to conceive of the grand project 

 of lighting by electricit} 7 a great eft}- from a 

 central station. That this could have been 

 accomplished without the careful training of 

 the German polytechnic schools, evidently im- 

 presses the author. 



Dr. Hagen corrects the impression, which is 

 evidently carried abroad in certain quarters, 

 that the whole of New York is lighted by the 

 Edison s} T stem. He computes that New York 

 proper covers eleven square miles, and the 

 portion lighted by Edison embraces only a 

 tenth of a square mile, and covers an area 

 comprised within a circle of a little less than a 

 thousand feet radius. A map of the region 

 covered by this S3'stem in New York is given ; 

 and the dimensions and construction of the main 

 leading wires, and the method of insulating 

 them in underground pipes, are fully described, 

 with a running criticism of the results that have 

 been attained. 



It is the author's opinion that large central 

 electric-lighting stations will be established 

 in all great cities, if the experiment in New 

 York does not show some at present unfore- 

 seen obstacles. The system of underground 

 wires forms, in his opinion, one of the greatest 

 obstacles. There is no doubt that the insula- 

 tion grows worse with time, and it is a 

 question how much of the electrical energy 

 is lost by defective insulation. He very prop- 

 erly remarks that the entire resistance of the 

 circuit, including of course the lamps, must 

 be considered, together with the loss of insu- 

 lation in the underground conductors, and that 

 even a ver} 7 large loss of insulation might not 

 consume more electrical energy than a single 

 lamp. 



The Edison plant is then carefully described, 

 and the dimensions of the various machines 

 fully given, together with the means of regu- 

 lating the current, the method of weighing it 

 and distributing it. We do not know where to 

 look for a more careful description of the con- 

 struction of the underground cables and the 

 method of insulation. The author concludes, 

 that, for equal amount of light, the Edison light 

 costs about a third more than gas. In spite 

 of this increased expense, the number of sub- 

 scribers has continued to increase since the 

 opening of the system, Sept. 3, 1883, and 

 great satisfaction has been expressed with the 

 light. Whether the system is suitable for 



