The mammoth wheel is
supported on two massive adjustable pedestals of cast iron weighing
twelve tons each, and its cost at the copper mines before making a
single revolution, $100,000.
Strength of Brick Walls.--The question of strength of brick walls is
often discussed, and differences of opinion expressed. The following
is one of the rules given:--For first-class buildings, with good
workmanship, the general average should not exceed a greater number of
feet in height than three times its thickness of wall in inches, and
the length not to exceed double the height, without lateral supports
of walls, buttresses, etc., as follows for safety:
THICKNESS; SAFE HEIGHT; LENGTH.
8-1/2 inch walls; 25 feet; 50 feet.
13 inch walls; 40 feet; 80 feet.
17 inch walls; 55 feet; 110 feet.
22 inch walls; 66 feet; 130 feet.
26 inch walls; 78 feet; 150 feet.
Where the lengths must exceed these proportions, as in depots,
warehouses, etc., the thickness should be increased, or lateral
braces instituted as frequently as practicable.
Qualities of Building
Stone.--The principal qualities of a good building stone are--(1)
Strength, (2) hardness, (3) durability, (4) appearance, (5) facility
for working. There are also other minor points; but stone possessing
one or more of the above qualities, according to the purpose for which
it is required, may be regarded as good for that purpose.
Pages:
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567