Where did the Ferris Wheel get Its Name?

The Ferris wheel was named after its builder, George W. Ferris, an able engineer, now dead.

The original Ferris wheel was exhibited at the Chicago World's Fair. It was a remarkable engineering feature.

Its diameter was 270 feet and its circ.u.mference 825 feet. Its highest point was 280 feet. The axle was a steel bar, 45 feet long and 32 inches thick. Fastened to each of the twin wheels was a steel hub 16 feet in diameter. The two towers at the axis supporting the wheel were 140 feet high, and the motive power was secured from a 1,000 horse-power steam engine under the wheel.

The thirty-six cars on the wheel each comfortably seated forty persons.

The wheel and pa.s.sengers weighed 12,000 tons.

By the Ferris wheel the almost indefinite application of the tension spoke to wheels of large dimensions has been vindicated, the expense being far smaller than that of the stiff spoke.

[Ill.u.s.tration: STEEL RAIL MILL

Interior view of the Bethlehem Steel Company's rail mill finishing department, showing the machinery for straightening and drilling rails.]

What is Done to Keep Railroad Rails from Breaking?

The breaking of rails has been the cause of much attention on the part of railroad and steel engineering experts ever since the tendency toward the construction of heavy locomotives and greater train loads became evident.

The report of the Interstate Commerce Commission for 1915 gave broken rails as the cause of 3,345 accidents, in which 205 people were killed and 7,341 were injured, with a property loss of $3,967,188. A steel man is authority for the statement that one cold winter day in 1913, a single locomotive, making excessive speed, broke about a hundred rails in the distance of a mile on one of the leading railroad systems.

Both steel and railroad men were, therefore, much interested in the announcement made by the New York Central Railroad, in August, 1916, to the effect that the road's staff of specialists had discovered the cause and remedy for the hidden flaws in steel rails. It was said that no rails produced under the specifications provided by them had yet developed any fissures.

The process by which those rails were prevented from developing fissures consisted mainly of rolling them from reheated blooms, and although that method is said to have been used in a number of rail mills for many years, no mention had previously been recorded of the prevention of breakage in that way. The experiments are, therefore, sure to be watched with a great deal of interest, and it is probable that fewer accidents will occur from broken rails in the near future.

The technical man will be interested in an outline printed in the _Iron Age_, which said: "Induced interior transverse fissures in basic open-hearth rails are due in part to an occasional hot rail being cooled so rapidly by the rolls or so chilled by the gusts of air before recalescence on the hot beds as to cause a log of some of the transformations of the metal in the interior of the rail head. Induced interior transverse fissures can only develop in the track from the effects of preceding causes, either of which is no longer a mystery."

The report of the railroad experts also laid stress on the theory that "gagging" rails--subjecting them to blows for the purpose of straightening them--was also likely to cause faults by injuring the metal.

How does a "Master Clock" Control Others by Electricity?

With the aid of electric currents, one clock can be made to control other clocks, so as to make them keep accurate time.

By means of this method one high-cla.s.s clock, usually in an astronomical observatory, compels a number of other clocks at considerable distances to keep time with it.

The clocks thus controlled ought to be so regulated that if left to themselves they would always gain a little, but not more than a few minutes per day.

The pendulum of the controlling clock, in swinging to either side, makes a brief contact, which completes the circuit of a galvanic battery, and thus sends a current to the controlled clock. The currents pa.s.s through a coil in the bob of the pendulum of the controlled clock, and the action between these currents and a pair of fixed magnets urges the pendulum to one side and to the other alternately. The effect is that, though the controlled clock may permanently continue to be a fraction of a second in advance of the controlling clock, it can never be so much as half a second in advance.

An electrically controlled clock usually contains a small magnetic needle, which shows from which direction the currents are coming. The arrangements are usually such that at every sixtieth second no current is sent, and the needle stands still. Any small error is thus at once detected.

The Story of the Calculating Machine

How did Men Learn to Count?

Historians tell us that man was able to count long before he was able to write. Of course, he could not count very far, but it was enough for his needs at that time. He had no money and very few possessions of any kind, so that he did not have much occasion to use arithmetic.

It was fairly simple for prehistoric men to distinguish one from two, and to distinguish a few from a great number, but it was more difficult for him to learn to think of a definite number of objects between these extremes. Those who have studied the evolution of figures say that man found it hard to think of a number of objects without using a mark or a finger or something to stand for each object. That is how the first method of counting came into use.

Because man had ten fingers and thumbs, he learned to count in tens.

When he had counted ten, he could make a mark to remind him of the fact, and then count them over again. Some of the early races learned to designate units from tens and tens from hundreds by working their fingers in various ways. Other peoples also made use of their toes in counting, so that they could count up to twenty without getting bothered.

Cantor, the historian, tells of a South African tribe which employed an unusual system of finger counting. Three men sat together facing a fourth who did the counting. Each of the three held up his fingers for the fourth man to count. The first man's ten fingers and thumbs represented units; the second man represented tens, and the third hundreds. By this means, it was possible to count up to 999.

Who Invented the First Adding Machine?

Early cuneiform inscriptions, made about 2200 B. C., show that the Babylonians had developed a fairly extensive system of figuring. This was in the days of the patriarch Abraham. When men's minds were overtaxed with the strain of counting into the hundreds and thousands, the Babylonians invented the first adding machine, a "pebble board," a ruled surface on which pebbles were shifted about to represent different values.

The next adding and calculating machine was an evolution from the digits of the human hand and is known as the abacus in China, and the soroban in j.a.pan.

The abacus may be defined as an arrangement of movable beads which slip along fixed rods, indicating by their arrangement some definite numerical quant.i.ty. Its most familiar form is in a boxlike arrangement, divided longitudinally by a narrow ridge of two compartments, one of which is roughly some three times larger than the other. Cylindrical rods placed at equal intervals apart pa.s.s through the framework and are fixed firmly into the sides. On these rods the counters are beaded. Each counter slides along the rod easily and on each rod there are six tamas or beads. Five of these slide on the longest segment of the rod and the remaining one on the shorter. Addition, subtraction, multiplication, division, and even square and cube root can be performed on the abacus, and in the hands of a skilled operator considerable speed can be obtained.

[Ill.u.s.tration: FINGER COUNTING WAS COMMON AMONG EARLIER PEOPLES, AND WAS BROUGHT TO A FAIR DEGREE OF EFFICIENCY BY SOUTH AFRICANS

_Courtesy of the Burroughs Adding Machine Company._]

[Ill.u.s.tration: THE "ABACUS" WAS ONE OF THE EARLIEST AIDS TO CALCULATION

It is still used extensively in China, and occasionally will be found in Chinese laundries in the United States.

_Courtesy of the Burroughs Adding Machine Company._]

The Oriental tradesman does not deign to perplex himself by a process of mental arithmetic; he seizes his abacus, prepares it by a tilt, makes a few rapid, clicking movements and his calculations are completed. We always look with some slight contempt upon this method of calculation, but a little experience and investigation would tend to transform this contempt into admiration, for it may be safely a.s.serted that even the simplest of all arithmetical operations, the abacus, possesses distinctive advantages over the mental or figuring process. In compet.i.tion in simple addition between a "lightning calculator" and an ordinary j.a.panese small tradesman, the j.a.panese would easily win the contest.

Blaise Pascal, the wonderful Frenchman, who discovered the theorem in conic sections, or Pascal's hexogram, was not only one of the foremost mathematicians of his day but also excelled in mechanics; when he was nineteen years old he produced the first machine for the carrying of tens and the first arithmetical machine, as we know it, was invented by him about 1641. This was the first calculating machine made with dials.

The same principle, that of using discs with figures on their peripheries, is employed in present-day calculating machines. Among these are numbering machines of all kinds, speedometers, cyclometers and counters used on printing presses.

[Ill.u.s.tration: A MODERN BOOKKEEPING MACHINE, USED FOR LEDGER POSTING AND STATEMENT MAKING

It has seventeen "banks" or rows of keys, is electrically operated, and automatically adds, subtracts, and computes balances.

_Courtesy of the Burroughs Adding Machine Company._]

Who Discovered the Slide Rule Principle?

It was early in the seventeenth century that Napier, a native of Naples, invented the first actual mechanical means of calculating. He arranged strips of bone, on which were figures, so that they could be brought into various fixed combinations. The instrument was called "Napier's rod" or "Napier's bones." It was the beginning of the slide rule, which has been found of invaluable aid to accountants and engineers.