All this shows an inequality of attempted retribution which is almost universal. A distinguished criminal judge in this country, after thirty years' experience, recently exclaimed, "I am by no means certain that I have ever given a correct sentence !

In the next place, arbitrary sentences are undesirable, first, as to the convict. If the true object of confining criminals is to protect society by secluding and reforming the offender, the only logical result is he should be confined till he is reformed. Nothing can be more absurd for the State to say to a confessedly unreformed convict, "You must be turned loose on society the moment the prison clock strikes twelve" on a given day; and yet, under our system of time sentences, a large majority of convicts are liberated who are avowed enemies of society, and intend to get their living by pillage and vio lence.

Again, time sentences are undesirable because of their effect on the criminal. If a man knows that his reformation has nothing to do with his release, a powerful motive for his reformation is withheld. The worst punishment which can be inflicted on a confirmed criminal is to keep him in confinement until his criminal impulses are removed. Such criminals prefer a long-time sentence at Sing-Sing to an indeterminate sentence to the Elmira Reformatory. If it is said that it is unsafe to intrust the power of discharge to prison managers, it may be replied that we are daily witnessing the same power exercised by experts in insanity, even where the insanity is homicidal, and we know that they often make mistakes which lead to fatal results, but nobody thinks of depriving them of this power.

A further step is indispensably necessary, viz., the permanent confinement of incorrigible offenders, in other words, professional criminals, for whenever a man has demonstrated that he cannot safely be at large, he has forfeited his right to be at large.

Prof. Wayland stated further that the principle of the indeterminate sentence for first offences has been legalized in New York, Ohio, Pennsylvania, and Massachusetts, and that the permanent confinement of incorrigibles had been legalized in Ohio and Massachusetts, and their confinement for twenty-five years in Connecticut.

A long and interesting discussion followed the reading of the paper, after which the meeting was brought to a close by a vote of thanks to Prof. Wayland for his very interesting lecture..

MEETING 389.

Electric Railways.

BY CAPT. EUGENE GRIFFEN, U. 8. A/

The 389th meeting of the SOCIETY OF ARTS was held at the Institute on Thursday, April 25th, at 8 P. M., President Walker in

the chair.

After the reading of the records of the previous meeting, and the transaction of some business, the President introduced Capt. Eugene Griffen, U. S. A., who read a paper on "Electric Railways."

Capt. GRIFFEN said: The electric motor is not the discovery of any one man. Some of the greatest scientists in history have contributed to the development of this machine. Barlow in 1826, Jacobi in 1884, Davenport in 1837, Davidson in 1838-39, Cook in 1840, Elias in 1842, Froment in 1845, Page in 1850, Du Moncel in 1851, and many others were pioneers in this direction. All those early forms of motors were of course actuated by voltaic batteries. Thomas Davenport, a blacksmith of Brandon, Vt., is entitled to the honor of building the first electric railway. In the autumn of 1835 he set up a small circular railway at Springfield, Mass., over which he ran an electro-magnetic engine. He exhibited this road in Boston, for two weeks, in December of the same year.

One of the most interesting of the early experiments in electric railways was that with the Page motor, in 1851. Prof. C. G. Page, of the Smithsonian Institute, had been working in this direction for some years. In 1851 he constructed a large motor, capable of developing sixteen horse-power. This was mounted on a car, and supplied with a current from a battery of 110 Grove nitric-acid cells. On the 29th of April, 1851, he made a trial trip from Washington to Bladensburg over the tracks of the Baltimore and Ohio Railroad. The distance of five miles was run in thirty-nine minutes. A maximum speed of nineteen miles per hour was attained on a level, and this speed was maintained for a mile, until one of the cells cracked, the battery being weakened proportionally.

All this early work was useful in stimulating scientific investiga tion and invention, and in gradually developing better forms of motors, and establishing the true principles on which they should be constructed. The commercial and practical results were nil.

Electricity is obtained from voltaic batteries by the consumption of the zinc plates. Zinc is too expensive a fuel to compete with coal. In the meantime the dynamo-electric machine had been developed, and in 1864 Pacinotti, for the first time, enunciated the prin ciple of the reversibility of this machine, which is the foundation of the modern method of transmitting electrical power to a distance. He described his machine as one that could be used to generate elec tricity on the application of motive power to the armature, or to produce motive power on connecting it with a suitable source of power.

A more sensational discovery of this principle of reversibility is related in connection with the Vienna Exposition, in 1873. Several Gramme dynamos were to be exhibited. A workman, seeing a pair of loose wires near one of the machines, connected them to the proper binding posts, and, to his astonishment, the armature immediately began to revolve. Upon investigation it was found that the other ends of the wires were connected with a machine in operation, the source of power being a steam engine. Whether the result was attained accidentally or purposely, it was undoubtedly the first instance of the transmission of power to a distance by means of an electrical current generated by a dynamo-electric machine. The future history of the world will be greatly affected by this discovery. The dynamo or generator and the motor are theoretically the If a steam engine be belted to an armature pulley, and the armature pulley be made to revolve, a current of electricity is passed through the machine, the armature is made to revolve, and by belting to the armature pulley mechanical power is available. In this way one dynamo will convert the mechanical power of the steam engine into electrical power, and the electrical power may be carried through the wires to the second dynamo, perhaps five miles away, where it is reconverted into mechanical power, and so made available for any desired purpose. The second dynamo is called the motor, and differs from the first, not in principle, but only in details which make it better suited for its special work. In this way we do away with the

same.

zinc fuel, and come back to coal, except in those places where we are fortunate enough to have water power.

A brief description of the dynamo or generator, and the motor, is essential to a proper understanding of this subject.

The modern dynamo-electric machine is simply an application, on a larger scale, of Prof. Faraday's discovery, that, if a wire be moved through the magnetic field of a permanent electro-magnet, a current of electricity is produced in that wire. A dynamo machine consists of a pair of field magnets, between whose poles or extremities revolves a soft iron rotating support, wound about with a series of coils of wire, in which the current is developed. The revolving body is called the armature. It is generally made to revolve by belting a steam engine to a pulley on the armature shaft. As each wire moves through the magnetic field of one pole of the magnet, the induced or generated current in the wire is in one direction; as the wire moves through the field of the other magnet pole, the current is in the opposite direction. The current taken from the poles of the machine or generator, as it is usually called, would therefore be alternating were it not for the device called a commutator. This consists of a copper cylinder on the armature shaft, divided into as many segments as there are separate coils of wire in the armature, each segment insulated electrically from the others, and connected with its own armature coil. This commutator revolves with the armature, and against it are pressed two copper brushes, as they are called, which do not revolve. These brushes are the current collectors, and when they are connected by a metallic wire, five inches or ten miles long, so as to close the circuit, a direct current flows through this wire as long as the armature is made to revolve. Without going into details, it is sufficient to say that the brushes are so placed that, as each segment of the commutator comes in contact with the brush, the induced current in the corresponding wire is flowing in a constant direction, so we have a direct instead of an alternating current. As a matter of fact, the armature is not made up of separate coils, but the connections are so made with the commutator segments that we may theoretically regard the coils as separate.

The motor is practically the same as the generator, except that the power applied is electrical energy, and the power obtained is mechanical. The current coming from the generator goes to the

brushes on the motor, thence to a segment of the commutator, and so to the armature coils. The wire with a current flowing through it in a given direction is repelled by one pole and attracted by the other. The powers of attraction and repulsion compel the armature to move; it revolves, and we have mechanical energy. We gear the armature to the car axle, and we have motion.

There are two general methods of using electricity for the propulsion of street cars:

1. The direct method, by conductors extending from the dy namo along the track.

2. The indirect method, by the use of storage batteries, secondary batteries or accumulators.

In the direct method the conductors may be overhead, under ground, or on the surface.

In the conduit system the conductors are placed in a conduit between the rails or between the tracks. The wires must be bare, and yet must be thoroughly insulated from the ground, a condition very difficult to obtain under such circumstances. A slot about fiveeighths of an inch wide gives access to the conductors by means of a contact plow; but, unfortunately, also permits the flow of water, slush, mud, etc., into the conduit. The present stage of the art in this respect is illustrated by the conduit on Boylston Street, in front of this building. It is not a success.

The overhead wire is suspended from poles by brackets or from eross wires, which span the street between poles on either side. When the street is of sufficient width, poles are placed in the center of the street between the two tracks, with bracket arms carrying the conducting wires. These poles are placed about 125 feet apart, and from actual experience are found to present little or no obstruction to traffic. The wires may be single or double. When single wire is used, the rails are utilized for the return current. When two wires are used, one wire carries the outgoing and one the return current. Contact is obtained with the wire by an over-running or an under-running trolley. The over-running trolley is a light carriage with one or more wheels resting on the wire. A flexible conductor carries the current down to the car. The trolley is pulled along by the flexible conductor. The objections to the over-running trolley are that it is difficult to keep the trolley on the wire, it is difficult to replace the