not just as well suited for electric lighting as a continuous current. But many years ago, when Sir FREDERIC SIEMENS, one of the pioneers in the applications of electricity, made a system of arc lighting, requiring a continuous current to operate the regulator in the upper part of his arc lamps, instead of trying to invent a form of regulator to feed the carbons which could be operated by an alternating current, he placed the commutator and brushes on the dynamo, producing a continuous current, and in that manner set for years the practice of electric lighting by continuous currents, although in the mean time there have been numerous devices for regulating the carbon-feeding mechanisms of arc lamps by alternating currents. Electricians have of late years begun at the place from which they were diverted a number of years ago to investigate and apply alternating currents for lighting and power purposes. These investigations have opened up a wealth of electrical principles and applications of which the world has just seen the beginning. One of these new forms of alternating currents is what is called the multiphase current, of which the electricity is generated in waves, - one wave following another before the first wave has been completed, using currents of electricity which will affect other apparatus by induction through space and without the intervention of metallic conductors, being as a matter of principle comparable to the results produced upon a telephone system when it receives by induction the noise of electric motors or the click of the messages transmitted along telegraph wires in juxtaposition to the telephone wires, or even the voice which is transmitted over other telephone wires. In its application to these multiphase motors I would say that the method of construction differs entirely from the motors hitherto in use. Instead of using commutator and brushes to transfer electricity from one part of the armature to the other, as has been already alluded to in the continuous current motors, the magnetism revolves through the magnet, causing the armature to revolve in exact synchronism with it. For purposes of comparison, the general arrangement of these motors may be compared to that of a hat brim, as representing the circular magnet, and a ball of twine stands for the armature, on the inside of which is a suitably wound collection of insulated wires joined together at the ends and not electrically connected to anything else. Electric wires from the generators are wound upon this circular magnet, and the wave-like currents which the wires carry produce similar magnetization travelling around and around through the magnet; and by this inductive effect to which I made allusion, electric currents are produced in the wires of the armature, so that it will be susceptible to the attraction of the magnet. The wires in the armature revolve, following the attraction of the magnetism circulating in the magnet. Dynamos similar in principle produce the waves of current which supply this motor; but, for economy in transmission, both as regards the small amount of wire and the small loss by resistance, these currents can be generated at a high electrical pressure, which is increased by transformers for the main wires, and then at the motors reduced to a very low pressure by transformers, which answer the same purpose as the reducing valve for steam, except that they can act in either direction to increase or reduce the electrical pressure. The other advantages of these multiphase motors are that, being without any brushes or commutators, there is no sparking. There is hardly a possibility of a burned armature. The motor, being operated by a succession of wave currents, will keep at a speed comparable to that of the generator as long as it can keep up. If overloaded, it will not run slower, but will stop. Under similar conditions of overloading, a continuous-current motor will burn its armature, unless defended by its safety fuses. Its regulation is very close, the variability of some tests being only one and one-half per‹ between no load and its full load. Such a motor will start under its full load, or even greater. In connection with such a system of electrical transmission of power, it is feasible to use a portion of the current for incandescent lighting without any interference. These motors can be stopped and started without the exercise of any particular skill, and can be enclosed for protection against dust and dirt in a case which merely allows for the protrusion of the shafting carrying the driving pulley. These types of motors, although new, have received thorough applications and exhaustive tests in the works of the electric companies engaged in their manufacture. It is, however, scarcely time for their use in commercial lines in this country, but they will be very fully exhibited at Chicago. It is this type of electrical apparatus which will be used in transmitting the power from Sewall's Falls on the Merrimack River, about four miles north of Concord, for power and lighting throughout the city of Concord, and also to any establishments which may be built on the large tract of land in the vicinity owned by that company. There is a capacity of 5,000 horse-power at this point, and it is expected that 3,500 horse-power will be distributed during the early summer. The uses of electric motors in connection with the transmission of power is becoming more widely extended, one of the best examples in this vicinity being that of the Page Belting Company, at Concord, N. H., where the power is distributed throughout their extensive new establishment by means of electric motors, for which the electricity is generated in the original works of this company. Mr. GEORGE F. PAGE, the president, informs me that the whole cost of the electrical apparatus was twenty per cent. less than would have been required for a steam plant applied in the usual manner. There is a further economy by reason of the elimination of much of the shafting required in connection with the transmission of power from numerous motors, in comparison with the shafting and pulleys which would have been required to distribute the power from a steam engine on the premises. The largest shafting now in these works is two and one-half inches in diameter; but if an engine had been used, the main shafting would necessarily have been at least five inches in diameter, and the length of shafting many times greater than at present, the difference in this respect being greater than in cotton manufacturing, on account of the greater distance between the various machines. In addition to safety and convenience, it may be interesting to note that this method of transmission has been carried out in such a way that there is not a single open hole through the floor for any purpose whatsoever, the openings for the steam pipes being packed around with asbestos. This transmission of the power from the old works is only temporary, as it is proposed to connect with the electrical power derived from the water wheels at Sewall's Falls as soon as that installation is completed. I have been informed that at a new cotton mill in South Carolina the power will be transmitted by wire to a motor driving the line shafting in each room. One of the latest applications of the electrical transmission. of power is in the Crocker-Wheeler Electrical Works, at Ampere, N. J., where a pair of copper rods answer as line shafting, and from them the connections are made at will to motors operating machine tools in various parts of the establishment. In some instances it has been preferable to drive short lines of shafting by motors, and to belt down in the usual way. In the former case the motor is attached directly to the machine, as, for example, under the headstock of a lathe, and in place of using the cone pulleys for variation in speed, or the clutch for reversing the direction of the motion. The lathe is controlled by the operator in a manner comparable to the usual way in which the motorneer of a street car controls the speed or direction of the car; and from these same wires every machine an incandescent lamp suitably protected guards is used whenever artificial light is necessary, and such a light can be placed on the carriage, or wherever it may be desirable to apply the light for the purpose of the work in hand. The operation of a calico-printing machine probably presents the greatest difficulties in the application of power of any machinery in textile manufacture. The machine must be driven at will with variable speed, and any shock in the gradations from one speed to another may impair either the machine or the product. The cloth must be moved at times to a slight extent, and the whole must be absolutely under the control of the operator. As an absolute statement, these requirements are almost an ideality. Up to the present time a double-cylinder steam engine to each printing machine has furnished the best method of driving, notwithstanding that the heat and the floor area occupied by the steam engine is necessarily an interference in the printing room. When the printing machine stops, the rolls sink into the blanket, and it requires an excess of power to start it, as if it were a heavily loaded team on a soft road. A recent application of electric motors has given practical results of the greatest importance in operating printing machines at the Dunnell Print Works in Pawtucket. At the time of their reconstruction after their late fire, in accordance with plans made by STEPHEN GREENE, C. E., a member of this Association, about two years ago, Mr. W. W. DUNNELL, wishing that the new print works should contain all of the improvements possible in the business, considered favorably the suggestion that electric motors should be tried for the operation of printing machines. A motor was applied to a seven-roll printing machine, in order to give the matter a thorough trial. This work was undertaken in spite of the skepticism of his associates and the opposition of the men engaged in the printing room. There were some difficulties at first, primarily owing to the fact that the electricians were not calico printers, as well as that the printers were not electricians. It required a little time for each to learn of the other; |