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MAGNIFIED COTTON FIBERS SHOWING CUTS AND
INJURY FROM SAW GINNING.

For years inventors have been working to improve the capacity of the roller gin, knowing that when the quantity of output would equal the saw gin, the latter would die out.

Some years ago Charles J. McPherson of South Framingham, Mass., became interested in the improvement of cotton ginning and as a result of his experiments invented what he calls the rotary comb roller gin. This gin will soon be in the market in competition with the saw gin.

The new gin uses a rotary process which gives it a rapid ginning action and a great capacity, turning out from 400 to 500 pounds of short staple cotton per hour while the fiber is uninjured and the quality of the lint perfect. Many points of superiority are claimed for this new gin over the saw gin. Among them is the saving in fire losses which now occur in saw ginneries through the action of the rapidly revolving saws encountering pebbles or small particles of hard metals which are frequently brought to the ginneries in the seed cotton. Sparks are flashed as a result and fires ensue, thus causing insurance rates on ginneries to be very high. The action of the rolls in the rotary gin is to smother the fire should one start in the gin. Repeated tests having been made to demon-strate this fact. There is no danger There is no danger whatever to operators of the new roller gin. Thousands of employes in Southern ginneries are maimed or less seriously injured each year by saw gins.

PERFECT COTTON FIBERS FROM ROLLER GIN.

great saving to him in the preliminary processes in the mill, besides making a stronger yarn. As a result roller gin cotton sells from one-half to three cents per pound more than saw gin cotton.

The gin consists of two sets of double rolls, the rolls of each set revolving in opposite directions. One of these is a ginning roll, and is covered with some soft material having a gentle friction-usually walrus hide-which will thus not only not injure the fiber, but likewise should be free from the danger of heating excessively. The other roll is a combing roll and consists of a shaft on which are set spirally two pointed soft metal disks. The lint on the seed is caught by the ginning roll and drawn inside a polished steel plate or blade against which the ginning roll revolves. This action holds the seed firmly against the dull edge of the blade and it is combed from the lint by the points of the rapidly revolving disks. After being detached by the comb roll, the seeds are forced through a grate underneath by the rotary action of the comb roll, and the lint, now free, is blown by means of a suction fan to a condenser in the rear of the gin. The simplicity and efficiency of the process

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TWO ELEVATORS IN

ONE SHAFT

By

H. G. HUNTING

F you have ridden up and down in the elevators of the big buildings of Chicago, you are more likely to feel that too little, rather than too much, space is given to elevators. Usually they are used to capacity. With this fact perfectly clear in his view, however, Jarvis Hunt, designer of big buildings, has made the astonishing announcement that twice too much space is used by the lifts, because-now, don't laugh-because two elevators can just as well run in one shaft as

not.

A few days ago, a group of Chicago capitalists paid $85,000 a front foot for a piece of State Street real estate. That means that, for a strip of ground one foot wide and running back one hundred feet to the alley, they gave cheerfully, not to say with alacrity, a sum that would make a snug little competence, at least, for most men.

Of course, they did not buy one strip alone. They bought several, side by side. Then they dug still deeper into their capacious pockets and brought forth a million or so and put up a building of magnitude and figured the value of floor-space as a basis for rentals. And the floor-space was valuable. It was worth enough to pay up-keep, interest and profit on that $85,000 per front foot and on the million or so invested in the building.

Floor space in that building rents for about five dollars a square foot per month, or say eighty dollars for an office twelve by sixteen feet. With twenty floors, each one hundred. by one hundred feet inside measure, such a building would have two hundred thousand feet of floor space. And two hundred thousand feet at five dollars a foot per month, would make a very pretty income on investment. But

The space doesn't all rent. There must be halls and walls. There must be stairways. There must be closets, janitors' rooms, rooms for control-stations for various apparatus, washrooms. There must be a light-shaft.

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There must be air spaces and space for pipings
for water and sewer and steam, and wiring for
electric service. Lastly-but not least, by any
means there must be space for elevators.

When you come to count it all up, it is
costly space that is given to all these things.
It keeps the profits down-somewhat, though
it is still popularly believed to be a profitable
investment, this building and renting of big
skyscrapers. But suppose that each elevator
in such a building takes a space six by seven
feet, including its running space. That's forty-
two square feet out of each floor for each ele-
vator. Suppose it requires ten elevators to
serve the building. Ten elevators would sub-
tract ten times forty-two feet for each of
twenty floors, or 8,400 square feet, in all, from
the rentable floor space of the building. At
five dollars-oh, well, it is easy enough to
figure it. That's $504,000 a year in floor space
given up to elevators. That's quite a sum.

The builders of the big skyscraper on State Street are giving up $504,000 every year for the purpose of lifting people in and out of the rentable floor-space. You may be quite sure that they have figured rather carefully about the necessities of the case before they have consented to any such thing. But a certain Chicago architect has come forward and proclaims that they are throwing away just onehalf of that big sum. Literally they are throwing it away-for it isn't going to anybodyit isn't doing anybody any good. It simply isn't coming in when it should be. Why? Because too much space is given to elevators.

Two elevators in one shaft! How? Well, of course, they can't be side by side, so they must be one over the other. And the plan is "so simple that it's a wonder nobody thought of it before," just as is every other useful idea that crops into man's head after years of blundering blindness.

There are two types of elevators in common use now in the great buildings. One is the kind that is lifted by cables-the other is the sort that is pushed up by a plunger. Mr. Hunt means to put a cable-lift elevator in the shaft, to start at the first floor and run "express,' without a stop below the tenth floor, serving the floors above the latter point. Beneath that elevator, he will put another to start at the basement and be pushed up by its plunger and run "local" to the tenth floor and back, serving all floors below the tenth. Between the two cars he puts a safety device to prevent possibility of collision and-there you are. It is simple to arrange the schedule so that the two

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cars can serve their respective floors without
interfering with each other.

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While the cable-lifted car is rising from the first to the tenth floor, the plunger car will be taking on its load for the floors below the tenth. While the plunger car is delivering and receiving passengers between the first and the tenth floors, the cable car will be doing its work between the tenth and twentieth. requires just about as much time to serve one floor as another, and in all well regulated buildings a perfect schedule is adhered to, so that there will be nothing new in this requirement. There is every reason to believe that the new plan will work and work well-to the saving of about half of that $504,000 in the State Street building, and considerably more than that amount in some of the Chicago buildings where fifteen or twenty elevators are required to serve twenty floors.

Suppose there are twenty buildings in Chicago that can save as much as that, by such a change of elevator methods-suppose there are twenty cities that have ten buildings each that follow suit-suppose there are a hundred more that have from two to five-and suppose that half the lower buildings, to say nothing of the higher ones can adopt adaptations of the plan? That leaves nothing at all to suppose about the results in savings, lower rents and greater profits, does it? And it's one more proof that we haven't been half so clever as we thought we were in the matter of economies. If all the inventors were to turn their attention to showing us where we Americans are wasters, as the efficiency engineers are showing the railroads, our much inflated conceit would look like a toy-balloon that is busted.

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FIG. 1. SUCCESSIVE MOVEMENTS OF A GULL, MADE BY AN OBSERVER FOLLOWING THE LINE OF ITS FLIGHT.

BIRDS AS AVIATORS' MODELS

A

TRANSLATED FROM LA NATURE

By

MRS. F. M. C. HOLLEY

MONG the unexplained things of nature that man has been fretting his brain over to little purpose as yet, is the fact that some birds have the power to holds themselves in the air without being dependent upon the beating of their wings. Direct observation of birds and the character of their flight has established the fact that birds of a certain size do not fly exclusively by beating their wings; they soar in the air. It may be said that this kind of movement is general with birds above the weight of four and one-half pounds, as if nature had not known how to enable large birds to use the same kind of flight as small

ones.

How, under these conditions can we hope that man, surpassing nature, should be able to make a beating of wings that will lift not merely four and one-half pounds but his own weight?

Works on the flight of birds, undertaken during the past few years are very numerous, and it is becoming difficult to find one's way amidst the contradictions, uncertainties and obscurities which one meets. However a certain number of facts have within this time been ascertained by the experimental method which have often been corroborated by careful calculations.

The sparrow gives the impression of a living force which raises itself quickly and flies with rapid beatings of the wings to traverse only a few yards or to raise itself to a slight elevation. The pigeon rises with the same facility, but its beatings are less rapid and are produced with much more regularity; its flight, more ample than that of the sparrow, gives the impression that it belongs to a more powerful bird, capable of sustaining its course a longer time.

But a new element appears in the pigeon's flight-the facility, of which it frequently makes use, of suspending the beating of its wings in order to glide through the air. through the air. In ordinary weather with a moderate wind it holds itself thus when from a high point it wishes to descend to the earth; it half folds back its wings and lets itself fall in a concave curve which may become ascending. This practice is frequently followed by swallows, swifts and hawks, which use the momentum gained during the fall in order to mount again. During this fall and this automatic ascension, there is no expenditure of force necessary on the part of the bird, which benefits by this rest in order longer to continue its flight. It is in this way that swallows succeed in ploughing through the air, almost without stopping, from morning until evening.

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