The Locomotive - Lighthouse Survival Blog

1893.] THE LOCOMOTIVE. ^57
ance the scale with Mr. Ferris' big toy. And the one is set immovable, resting on two
supports, while the wheel is swung upon an axle lifted one luindrcd and forty feot in
the air. It has thirty-six cars, and in those two regiments of soldiers could ])e seated
and swept with an almost imperceptible motion high above the Wl^te "Wonder.
I said : " Precisely what does the great wheel represent in mechanics ? *' " Well,"
Mr. Ferris replied, " I suppose you might consider it as typifying the present progress,
the latest development, of meclianical engineering. You know there are really two
wheels, one built thirty feet within tlie other. These are joined by truss work, such as
is used in our finest bridge construction. Beyond all that, the wheel develops to a de-
gree hitherto never realized the capacities of a tension spoke. You know that the^
wheel is not only a perfect pinion wheel, but a tension wheel as well, and the.se, I sup-
pose, may be regarded as its chief points. I do not know whether you have stopjjcd to
consider, but it is as perfect a pinion wheel as the little wlieel that goes flicking back and
forth in your watch. In all that immoiise diameter there is less deflection proportion-
ately, from a true circle, than from the pinion wheel of the most perfect watch made.
This is due to the fact that it has, instead of stiff" spokes, the tension or jointed spokes.
When I first proposed to build a tension wheel of this diameter the feat was regarded as-
impossible. It was held that the spoke rods on the upper side of the wheel at any given
moment, instead of sustaining the weight of the upper part of the wheel, would, from
their own weight as they hung vertically, pull down the arc of the wheel which they
bore upon, and thus cause the wheel to become elliptic. As a matter of fact, they do-
nothing of the kind. There is absolutely no deflection from the perfect circle.
"Considering some of the mechanical difficulties in the construction of the wheel,
you will note that it stands directly east and west ; thus the .southern side of the
wheel receives the entire brunt of the sun's rays, whereas the northern side is not only
shaded by the southern, but by the cars as well, causing a diflference in expansion vary-
ing from the heat to which it is subjected of from three to six inches. All these little
problems had, of course, to be met, for even this slight variation of five or six inches in
the total diameter of two hundred and fifty feet would be sufficient unless properly dealt
with to cause a disturbance in the working gear.— JVeic York Observer.
Explosion of a Steam Mang-le.
On August 24th a steam mangle exploded in the Hell Gate laundry, on East 104th'
street, New York city, and nineof the ten persons in the room were hurt, three being scalded
so badly that it was thought probable they would die. The mangle that exploded was
42 inches in diameter, G feet 8 inches long, and 1^ inches thick. It was blown from its-
fastenings, and hurled against the rear wall of the building. This wall abuts on the
side wall of a Second Avenue tenement, and the two walls have a united thickness of 32
inches. The mangle smashed a hole ten feet long and four feet wide throuiih this wall,
and piled a ton or more of bricks and mortar on the floor of the kitchen of the tenement
(which, fortunately, was not occupied). The engineer, Martin Phelan, was placed
under arrest. He .said he had 64 pounds pressure on the boilers, and could not account
for the explosion. A Mr. J. W. Cameron, who had been engineer at the laundry until
last July, offered a few observations on the subject of the explosion, and these, if he be-
correctly reported, prove him to be a philosopher of unusual calibre. " He said thnt
the laundry girls had told him that the steam exhaust pipes from both cylinders [mangles]
had got out of order. This would tend to permit the steam to condense in the cylinders.
The water thus formed would lessen the steam space in the cylinders, and if the girl.s.
did not watch the gauges carefully it was enough, Cameron said, to cause the explosion."