150 



SCIENCE. 



[Vol. VI., No. 133. 



a push, thus allowing the joints in the rails to 

 be smoothly passed. The reversing is accom- 

 plished as in the Daft, by employing an extra 

 pair of brushes. The speed of the car will be 

 controlled by the friction -brake, the motor 

 running constantly at a uniform speed. The 

 Eames vacuum brake will be employed, the 

 pump of which will be run by the motor. 



It will be seen from the above, that the Edi- 

 son-Field combination are working upon a new 

 principle. This sj^stem will have man}- advan- 

 tages peculiar to itself. Each car will be 

 independent, and the cars composing the train 

 will start off simultaneously, thus relieving the 

 elevated structure of the great strain caused 

 by the locomotive when starting. The con- 

 stantly' revolving armature, on account of its 

 high speed, and consquently great momentum, 

 will help start the train, thus relieving the 

 engine at the central station of sudden and 

 great strains. As the load on the car increases, 

 the traction likewise increases. The weight, 

 moreover, of a train of this kind, is more evenly 

 distributed than in one moved In- a locomotive. 



The electric motor, in general, possesses 

 advantages which are of special value on an 

 elevated road. It is possible to balance an 

 electric motor, thus relieving the structure of 

 the constant vibi'ation caused b}- the quickly- 

 moving locomotive. Its freedom from dust 

 and smoke, as well as its econom}', insure its 

 immediate introduction. 



Although the progress in introducing the 

 electric motor on the New-York elevated rail- 

 way has not been so rapid as had been antici- 

 pated by enthusiasts, still the progress has 

 been steady, and in the right direction. It is, 

 perhaps, remarkable, that more companies have 

 not commenced operations ; but when the mag- 

 nitude of the task is realized, and the patents 

 held by a few parties are inspected, the reason 

 is seen. However, several other companies in- 

 tend to commence operations in the immediate 

 future, the plans of which are now maturing. 



F. A. PiCKERNELL. 



A SCHOOL FOR ELECTRICAL ENGI- 

 NEERING IN BOSTON. 



The wonderfully rapid advances which have 

 been made during the past fifteen years in the 

 technical applications of electricit}' have taken 

 place at so swift a rate, that the progress of in- 

 vention has frequentl}' been such as to outstrip 

 the technical knowledge necessary- to apply 

 its results successfully and economically on a 

 commercial scale. Within the period men- 



tioned, the arts of quadruplex and multiple 

 telegraphy, telephony, electric lighting on a 

 large scale, and the electrical transmission and 

 distribution of power, have come into being, 

 while an enormous extension has taken place 

 in many of those branches which, like ordinary 

 land and submarine telegraph}', have been 

 practically suc.cessful for a longer time. And 

 almost simultaneously with this development 

 of the practical applications of electricity, and 

 largely on account of it, has come a corre- 

 spondingly rapid and important development 

 in electrical theor}', and in the construction of 

 accurate instruments for electrical measure- 

 ment ; so that engineers with an electrical 

 training limited to the small amount which, until 

 recently, was all that could be obtained in our 

 colleges and scientific schools, have found 

 themselves ill prepared to deal with the prob- 

 lems forced upon their consideration. In fact, 

 a new profession, that of electrical engineer- 

 ing, had suddenly opened, and neither the civil 

 nor mechanical engineer was well prepared to 

 pursue it. 



Up to the summer of 1882, no adequate pro- 

 vision appears to have been made by our scien- 

 tific schools for the technical training of young 

 men desiring to enter this profession ; but at 

 that time the Massachusetts institute of tech- 

 nology, recognizing the need of such instruc- 

 tion, decided to establish a course leading to a 

 degree in electrical engineering. This course 

 has gradually been brought to a state of com- 

 pleteness, until at the present time, besides a 

 few who have very recently graduated, there 

 are about fift}' students who are pursuing it. 



The course requires four 3'ears for its com- 

 pletion. During the first year the time of the 

 student is occupied with general preparatory 

 studies in mathematics, chemistr}', drawing, 

 and the modern languages ; and no one is 

 allowed to enter upon any of the professional 

 work of the later years who has not done very 

 creditably in the two first-mentioned studies. 

 The professional work, which extends through 

 the three remaining years, is based upon a 

 thorough study of general physics, mathemat- 

 ics, and mechanical engineering. The theory 

 of electricity, and practice in electrical meas- 

 urements, are pursued simultaneously in the 

 lecture-room and laboratory, the student learn- 

 ing the use of the different forms of apparatus 

 ordinarily used in electrical testing. A knowl- 

 edge of the calculus, and of analytical and ap- 

 plied mechanics, is assumed in the professional 

 studies of the course ; and works of reference, 

 or, if desirable, text-books written in French 

 and German, are freel}' used. A yqvj con- 



