HE unsophisticated visitor at an up-to-date structural iron or boiler shop, or great foundry or ship yard, will view with amazement the peculiar actions of some of the cranes in use. On the end of the hoisting-chain will be seen a strange-looking circular metal arrangement; the chain descends, the contrivance drops with a resounding clatter into contact with a huge boilerplate, or a pile of pig-iron, and instantly ascends again with the plate or a dozen rough, scorious pigs hanging to it in the most incomprehensible manner. The crane runs briskly along the over-head runway until it reaches the furnace platform, where the pigs suddenly release their hold, toppling to the floor with a startling clash which vividly shows their solidity and weight.

Were the plant in Salem and the time ancient, the whole management would probably be hauled up for witchcraft, but in these hard-headed times we naturally look around for the shop order, "Use No Hooks." And to the inquiring man who has any knowledge of electrical appliances the answer, "Electro Magnets," is explanatory.

One of these lifting magnets will pick up a safe weighing fifteen thousand pounds and, with a traveling crane, transport it se

curely from one shop to another. It will pick up a ship plate forty feet long, eight feet wide and one and one-eighth inches thick, and hold it against the vertical frames of a vessel while it is being riveted in place. It will take a highly finished and polished cylinder from the machine shop and deliver it to the assembling floor without the slightest chafe or scratch from chains or hooks. You may glide it six inches above the floor of a

GENERATOR WEIGHING 800 POUNDS.

car from which pig iron or scrap has been unloaded and every scrap and grain of metal will be attracted and held, leaving the dirt. Six hundred pounds of such chips have been so picked up at one

sweep.

Broadly stated, lifting magnets consist

of electric coils, enclosed in a casing of cast iron or steel. A variety of forms and sizes are made, that most generally used for handling pig iron and scrap being circular in form and from thirtyfive to fifty inches in diameter. Square magnets are used in handling sheet and

bar metal, small castings, and similar forms.

Of course, all lifting magnets are electro magnets; going into or out of service at the pressing of a button, or the turning of a switch.

The true magnet, or lodestone, was well known to the ancients. About the year 31 B. C., Strabo, the Greek philosopher-evidently the Jules Verne of his day-wrote an account of a chimerical correspondence between two friends by the help of two magnets which possessed such virtue that when one was moved, the other, "at never so great a distance," moved at the same time and in the same manner, thus enabling the friends, by means of an alphabetical dial,

to converse with each other, although separated by the width of a continent-a yarn strangely prophetic of the recent wireless telegraph inventions. The power of electricity to induce magnetism in common iron or steel was discovered in 1820 by Oersted and, although this property was early made use of in telegraph instruments and ex

with the time element of the magnet and can drop plates singly when and where. desired.

In handling scrap at the scrap pile the lifting magnet finds one of its greatest fields of utility. Such material is exasperatingly difficult to turn over and load up by hand. There are broken castings of every size and shape-loose wire

scrap, plate clippings, rail butts
and billets, punchings, and turn-
ings, all in inconceivable confu-
sion and aggregation.
Such ma-
terial is picked up from loose
piles, or off of cars, in masses or
clusters weighing from 500
to 1,500 pounds each, and
the action of picking up and
letting go is, of course, in-
stantaneous. At large foun-

perimental dynamos, it was not until very recently that the lifting magnet, with its enormous commercial economy in handling difficult material, was developed.

Such magnets, of proper design, will pick up five or six boiler plates or tank heads at one time, distributing them about the shop singly, if desired, by simply opening and closing the switch which contains the magnet. As the magnetic flux dies out the lowermost plate drops first, and if the switch be quickly closed the remaining plates will be held. The crane operator becomes familiar

dries the cost of handling this class of material has been reduced to one-quarter of the cost of former hand labor, and a great saving of room, also, may be effected by high piling, sometimes to twentyfive or thirty feet, which would, of course, be impracticable by hand labor.

In handling pig iron the efficiency of the magnet has been even more fully demonstrated. At a trial made last summer at the Youngstown Sheet and Tube Company's works, a steel gondola car containing 109,000 pounds of pig iron was unloaded in two hours and five minutes, one man only-the crane operator -doing the work. The average weight of each lift was 785 pounds, and the total cost of current used was twenty-five cents. Since that time even better results have been attained, it being stated that it is no unusual thing to unload 100,000 pounds of pigs in thirty minutes.

But it does still more valuable workthis astounding magnet. Picking eight

or ten hundred pounds of pigs from the stock pile it is run over the cupola, lowered well down into it, and made to deposit its load with comparative gentleness upon the coke. It charges the furnace much more quickly than can be done by hand, and requires but one-fifth the number of men; besides the very important fact that the coke is not crushed down, as happens when the metal is thrown in by hand. In blast furnaces a sow and pigs may be lifted by a magnet from the casting floor while yet hot, thus releasing the floor in much shorter time than was possible by hand. And in plate mills the plates, hot from the straightening rolls, can be picked up and carried out by a magnet before they have cooled off sufficiently to be operated on by hand.

A very interesting contrivance is the skull cracker. It is always situated at the scrap pile, and consists of a heavy iron bulb which, ordinarily, is raised by a derrick to a height of thirty or forty feet, and then released by a latch and allowed to drop upon some large piece of scrap beneath, breaking it up into pieces small enough to throw into the cupola. In this case the bulb frequently

rolls over with the eye underneath, and a gang of men is required to turn it so that the hook may be inserted for another raise. another raise. Since the bulbs weigh from 6,000 to 12,000 pounds each, the toil and delay in this operation are very great. But with the lifting magnet no eye is required. The magnet takes hold, no matter in what position the bulb lies, and the whole operation is greatly facilitated and expedited. And, when necessary, larger bulbs than ever before-up to 20,000 pounds-are being used.

Coming down to smaller achievements, the lifting magnet is found in several of the British navy yards and arsenals, handling shot and projectiles; and on one vessel, at least, this implement is being installed for conveying ammunition from the magazines to the turrets. In a wholesale hardware store at Pittsburg the lifting magnet is used for handling and storing kegs of nails and rivets-the keg heads proving no obstacle to the attractive force. Perhaps this will be more obvious when the statement is considered that, in actual service, an eighty-pound pig will jump from four to six inches, vertically, to meet the magnet. In this warehouse many other articles, boxed