any textile manufacturer to run the risks of the experiments when they are still in a crude condition. The investigation is going on under the processes necessary to adapt fuel oil to metallurgy, to the end that by-and-by it is probable you will get the results yourselves, without any doubtful or dangerous experiments.

Mr. FISH. I would like to ask Mr. Atkinson what he considers the dangerous features to-day, as it is applied.

Mr. ATKINSON. I think the chance is that liquid fuel may be as safe as coal if proper attention is given to the plant. We have had our fears of danger allayed since the matter first came up, and the right directions were given for putting in the plant. We draw our lines where the plant was not put in in a proper way; but since it is now a necessity to use liquid fuel in some branches of metal working, not merely a questionable matter of expediency in making steam, it is better to keep on the safest side until absolute assurance of safety may be given.

The PRESIDENT. Many of the older members, at least, remember that Mr. OLIVER P. HUSSEY was a very active member of the Association, and contributed largely to the literature that we have in our published volumes; and I have great pleasure in introducing Mr. O. S. HUSSEY, a nephew of that gentleman, who will read a paper on Electricity in Mill Work."

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A MEMBER. Before beginning I would like to make one remark. If it is a long paper I would suggest, as time is so valuable, that he read only the principal items, passing over the minor ones; and then give opportunity for remarks and for questions. It will give more time for discussion.

The PRESIDENT. If that is the pleasure of the members I have no doubt Mr. HUSSEY will follow the suggestion.

ELECTRICITY IN MILL WORK.

BY O. S. HUSSEY, BOSTON, MASS.

During the past few years, the applications of electricity to power transmission have increased to such an extent that one can hardly realize it is a little more than ten years ago that electricity became of practical use to the commercial world. This increase is due to the great economy obtained in electrical transmission, and to the flexibility of the apparatus employed, when installed under suitable conditions.

Electricity is used to-day for transmitting thousands of horse-power in units as small as one-eighth horse-power and as large as three hundred horse-power, one as successfully as the other, over distances ranging from five hundred feet or less to five miles and more.

Inasmuch as the terms used in electrical parlance are doubtless more or less unfamiliar ones to you, it might be well perhaps to give you definitions of some of the most

common ones.

It is quite admissible to say that there are some quantities in electro-technics which have similar functions to distance, weight and capacity in mechanics, and that the analogies to these may be used to illustrate the nature of the different electrical phenomena.

This can best be shown by a mechanical illustration.

We all know and understand the construction of an ordinary steam-pump; when in action it sucks water from a lower level and raises it to a higher level. If the upper level is connected by a pipe or other means to a lower level, a

current will be set in motion from the lower level through the pump to the upper level and thence through the pipe back to the lower level.

The pressure of the water which is derived from the pump, being of a positive nature at the delivery end and negative at the suction, corresponds precisely to the electrical pressure or potential in batteries and machines.

In both cases, if they are allowed to equalize themselves, current will be produced in a certain direction, from the positive to the negative in the external circuit, and from the negative to the positive through the machine or battery itself. This pressure corresponds to pounds per square inch in mechanics, and is called, in electrical work, electrical pressure, electro-motive force or potential, and is measured in volts.

This pressure is measured from some zero point; in the case of water the zero point is the ocean, while the zero point in electricity is the earth, and is the natural pressure of electricity in the earth itself.

In electrical phenomena an electro-motive force is necessary to create a current of electricity. This current, expressed in amperes, represents the quantity per second.

There is also an electrical resistance (measured in ohms) which opposes the passage of an electrical current through a conductor, just as in mechanics a frictional resistance opposes the passage of water through a pipe.

The electrical resistance increases with the length of the conductor and diminishes as the area of cross section increases. It also depends upon the nature of the material used as the conductors. This material used for conductors is almost invariably copper wire. It has seldom been found advisable to use a wire larger than No. 0000, Brown & Sharpe gauge, because of the difficulty in handling. The amount of power this size of wire will transmit depends upon three facts, the distance to be transmitted, the voltage used, and the loss of power to be allowed in the transmission.

For example: allowing a loss of power of ten per cent. in the transmission, a single No. 0000 wire will carry sixty horsepower a distance of 5,471 feet at 500 volts. Allowing a loss of twenty per cent. in the transmission, the same size wire will carry sixty horse-power about 12,300 feet, using the same voltage. That is to say, the same amount of power can be forced through the wire a greater distance if a greater proportional loss in the line is allowed. In the first case, the actual loss on the wire would be about seven horse.power; in the second, about fifteen horse-power. The power lost in the line reappears as heat, the rise in temperature having a definite relation to the amount of power lost.

The above, then, briefly defines the three most common terms used in electrical work of all descriptions.

The question of long-distance transmission of power by electricity is one which has only been recently considered by engineers. If a mill is located upon a water-power which is only sufficient to furnish enough power for a portion of the year, it has always been considered necessary to put in an engine of sufficient capacity to "help. out." The fact that the power of a fall, located at some distance from the mill, could be utilized at the mill in connection with the power already there, through the medium of electricity, has not even been thought of.

The writer has in mind a mill which is located under similar conditions. A one thousand horse-power engine is installed at the mill, and whenever necessary is run in connection with the wheels. There is a water-power about two miles from the mill of over 2,000 horse-power capacity. How easy it would be to transmit this power to the mill, by proper electrical apparatus, and use it instead of the engine! The Thomson-Houston Motor Company is at present building a generator and motor for use near Hartford, Conn., and the amount of power to be transmitted is three hundred horse-power. The source of power is ten miles away from where power is to be used. It is proposed to use in this case three thousand volts, owing to the great distance carried.

Again, a large paper company, located near Portland, Me., is driving its entire mill by electric power, which is transmitted a considerable distance. The voltage used in this instance is only five hundred, as the power is subdivided into small units and distributed throughout the mill.

The province of this paper, however, is not so much the consideration of the subject of long-distance transmission as it is to show, if possible, how electric power can be used advantageously in performing some of the work, in and about a mill, now done by other means.

This work may be divided under the following heads :1st. Electricity as applied to isolated motors, located in different parts of a mill, and used to drive lines of shafting, separate machines, etc.

2d. Electricity as applied to driving tram cars suitable for handling all classes of goods, both in the mill and about the mill yard.

3d. Electricity as applied to hoisting machinery of all descriptions, including elevators, whip and drum hoists,

etc.

4th. Electricity as applied to pumping machinery.

Assuming that there is sufficient power at the mill, either steam or water-power, let us then consider what is necessary in the way of generators for supplying power to the different electrical apparatus, wherever located.

Fig. 1 shows a generator of eighty-five horse-power capacity, suitable for power transmission, manufactured by the Thomson-Houston Electric Company.

It is equipped with a sliding base and self-oiling bearings. The weight of this machine complete is ten thousand pounds. This same company builds generators of this design in capacities ranging from five horse-power to one hundred horse-power. It also builds machines, but of another type, of one hundred and fifty horse-power, two hundred and fifty horse-power, and three hundred horse-power.

For transmitting over distances such as would occur about a mill, both generators and motors should be wound for five