titions and prime mover are omitted. The great driving wheel takes motion direct from a 450 horse-power Corliss engine. It is 22 feet in diameter and weighs 27,000 pounds. It has 14 peripheral grooves for the one and one-fourth inch main driving rope, which is endless, and passes fourteen times around the driving and main driven pulley on the jack shaft. It also on its course passes around the main slack take-up, which preserves a uniform tension on all parts of the rope.

From the jack shaft, power is distributed to various departments of the works by separate transmissions, the driving wheels of which bave each a friction clutch whereby they may be coupled to or liberated from the jack shaft without disturbing the motion of the engine or other distributing transmissions. This economizes power by making the connections near the prime mover. On the drawing, four of these supplemental transmissions are shown. They pass from the jack shaft vertically about 50 feet to the leaders in the tower, and then pass direct in four different directions to the driven shafts, the furthest being in this case more than 600 feet away. It will be observed that while two strands of the driving rope transmit the power there are four strands around the wheel on the jack shaft. The extra two pass around winder wheels, two of which are shown separate from the leader wheels, and are used solely for the purpose of increasing area of contact with the driver (and the same at the other end to secure increased contact with the driven). The number of such extra passages may be more or less, as may be necessary to eliminate the slip. The leader wheels may be set at any angle as to the axis of the driving wheel, and therefore the power may be transmitted in any desired direction without limitation.

Distance and direction are practically immaterial, and the loss in transmission is confined to aerial friction and the friction of bearer journals, slip being eliminated. These advantages being demonstrable, it has naturally followed that this way of transmitting power has been adopted for long-distance transmission more rapidly than in locations where belts can still be employed without marked difficulty. In connection

with rope transmissions over considerable distances, the friction clutch has assumed a new importance as a factor in the distribution of power; and the long transmission with the friction clutch, rendering it possible to concentrate the power in a single source and distribute it from a central station, renders electricity, as a means for control, of importance only second to the rope as a transmitter. Under the old systems, and under all the present systems of rope transmission except the Dodge American System, the engineer is depended on to disconnect or connect the transmission with its driver. Necessary communication is usually by means of a signal bell worked by the pull of a wire. In a few instances the signals are transmitted by electricity. At the best this is a slow method, altogether too slow when prompt action is necessary to save life or destruction of property. At the moment of getting the signal the engineer may be engaged, and in the absence of any knowledge of special necessity for haste precious moments may be lost before the clutch is thrown out.

To obviate these difficulties and to give direct control of the transmission to those at the driven end of it, Dodge Manufacturing Company have an electric let-off, by means of which the clutch may be thrown out instantly, by closing circuit at any one of several places located about the works at convenient points.

In this instance the clutch lever is provided with a short rack, and a pinion on an upright shaft meshes therewith. The upright shaft carries a rope segment and a bevel wheel at its top. A rope on the rope segment carries a weight sufficient, when liberated, to pull the clutch out. The bevel wheel at the top of the upright shaft meshes with a pinion on a horizontal shaft, the other end of which enters the let-off box and carries the stop wheel, which is arrested and held by a pawl within the box. There is also a hand wheel by means of which the clutch is "set" and the weight wound up. When so "set' and wound up, it is held by the pawl in engagement with the stop wheel. As will be easily perceived, the pressure upon the end of the pawl will be considerable, and to disengage it by a direct electrical pull would require an undesirably large battery power. The required liberation is therefore effected by a dropping weight and the force of the blow, which within a small compass may be rendered more effective than a single pull. The weight consists of a rod which may be weighted to any desired degree. It is sustained by a hooking lever the end of which is supported by a swinging armature latch. An electro magnet in the electric circuit withdraws the armature latch and liberates the dropping weight whenever circuit is closed at any closing point in the circuit, and these points may be as numerous as desired and placed at such points about the works as may be most convenient.

For convenience, an electrical annunciator is also placed in the circuit in the engineer's room, and he is thereby informed when a clutch has been "thrown out," and also signalled when it is desired to "hook up" again.

In the above we have described the gear as it is set up under the particular arrangements in Dodge Manufacturing Company's works. It is evident the connections between the let-off box and the clutch may be modified to suit the circumstances of

any case.

It is one of those conveniences which become necessities as soon as used; and no user of one of these transmissions and electric let-off systems would be willing to discard either under

any circumstances. It is an instance in which the cost of maintenance sinks into insignificance beside the advantages derived from its use.

APPLICATIONS.

The process is far cheaper than any other system for longdistance transmissions, and is fully as cheap for short distances as belting, and about 15 to 20 per cent. more efficient, as no loss is sustained by rapid bending of the belt or slip to overcome its thickness. For in case a transmission is rigged for a 500 horse-power transmitter, more or less, and a given number of wraps of rope and tension weight proper for such a power is used, it may, without expense to journal friction, be changed to 200 horse-power by relieving the tension weight and thus converting, at will, a heavy transmission into a lighter one, with a large saving in power.

As a matter for comparison I will submit the following in the main transmission at the Dodge Manufacturing Company works:

To transmit the same power with a rope versus a like power with a wide belt,

(1) Requires much narrower-faced pulleys; consequently less expensive.

(2) The interest on the money required to be invested in a large belt will more than supply the rope, saying nothing about wear and tear.

(3) Better power by fully 15 per cent., from the fact that all slipping of the belt is overcome, and the rope gear, if of sufficient capacity, becomes as positive as a cog gear.

(4) The transmission in question consists of a series of grooved wheels and a cotton rope; the driver, 22 feet diameter, 14 grooves, driven 8 feet diameter, 15 grooves, winder pulley used to convey the rope to the slack carriage; this togeth with the carriage pulley are each two grooved and 60 inches diameter. The device for taking care of the slac the proper tension to the rope in a movable carri: which works automatically, being impelled by a

This apparatus including as above:

One 22′×14 groove wheel, 27,000 pounds, cost 7 cents,
One 8'15 groove wheel, cost, .

$1,890 00 212 00

60 00

100 00

88 66

$2,350 66

Millwright work about the same as for a belt transmission. Total cost of rope drive, $2,350.66.

To put in a belt drive with same speed would have required:

One 22′40′′ face wheel, 30,000 pounds, cost 7 cents,
One 8'x40' face wheel, cost,

132 feet 40" double leather belt, cost $6.30 per foot net,

$2,100 00 356 00

771 75

$3,227 75

Probably a tightener would be required, costing at least two or three hundred dollars more.

The above apparatus was erected and started in December, 1888, and has been running constantly since with the same six splices and transmitting an average of 450 horse-power.

The rope, when first put on, was allowed to run until the outside threads became worn and looked woolly. The rope was then treated to a bath of filler compound of tallow, beeswax, molasses and rosin applied hot. It now has the appearance of worn rawhide, and in fact is beautiful. It shows no signs of wear and looks as though it would last for years to come.

The rope drives from the jack shaft, shown in the large cut, are all manila ropes manufactured from the best selected long fibre, and in laying them up they are filled with tallow, paraffine and steatite, which lubricates them and prevents grinding out. These several drives have been in constant use since 1888, and are still running with their original splices. They are apparently as good as new. I will add, they have been treated with the mixture named, tallow, molasses, rosin, etc., as often