courtyard. It is a three-lift telescopic one; the lowest lift being 200
feet, the middle lift 197 ft. 6 in., and the top lift 195 ft. in diameter.
The height of each lift is 40 feet. The several lifts are raised in the
usual way; and they all work in a circle of 24 vertical U-shaped channel
irons, fixed in the wall of the house by means of 13 supports placed at
equal distances from the base to the summit (as shown in Fig. 2). When the
gasholder is perfectly empty, the three lifts are inclosed, one in the
other, and rest with their lower edges upon the bottom of the tank. In this
case the roof of the top lift rests upon a wooden framework. Fixed in the
floor of the tank are 144 posts, 9 inches thick at the bottom and 6 inches
thick at the top, to support the crown of the holder in such a way that the
tops are fixed in a kind of socket, each of them being provided with four
horizontal bars, which decrease in thickness from 305 by 100 mm. to 150 by
50 mm., and represent 16 parallel polygons, which in their turn are
fastened diagonally by means of iron rails 63 by 100 mm. thick, arranged
crosswise. The top of this framework is perfectly contiguous with the
inside of the crown of the gasholder. The crown itself is made up of iron
plates, the outer rows having a thickness of 11 mm., decreasing to 5 mm.
toward the middle, and to 3 mm. at the top. The plates used for the side
sheets of the holder are: For the top and bottom rows, 6.4 mm.; and for the
other plates, 2.6 mm.

* * * * *

A new bleaching compound has been discovered, consisting of three parts by
measure of mustard-seed oil, four of melted paraffin, three of caustic soda
20 deg. Baume, well mixed to form a soapy compound. Of this one part of weight
and two of pure tallow soap are mixed, and of this mixture one ounce for
each gallon of water is used for the bleaching bath, and one ounce caustic
soda 20 deg. Baume for each gallon is added, when the bath is heated in a close
vessel, the goods entered, and boiled till sufficiently bleached.

* * * * *

GEORGE W. WHISTLER, C.E.

[Footnote: A paper by Prof. G.L. Vose, Member of the Boston Society of
Civil Engineers. Read September 15, 1886.]

By Prof. G.L. VOSE.

Few persons, even among those best acquainted with our modern railroad
system, are aware of the early struggles of the men to whose foresight,
energy, and skill the new mode of transport