AND BUILDING CONTRIVANCES.North Gallery, and with Ci.asses 5 & 6.
319
Kingdom.]
TUNNEL
LOWEST 13RIDCE'BETWEENLONDONAXD HOLYHEAD
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Scale of eight feet to an inch.
Scale of eight feet to an inch.
97
u n<le]S Cal water -whcel, to be used as a breast-wheel, oras to oh ^eel, having governor-paddles so constructed
thp - uv ^3>te the back-water and incren.se the effieienev of
Inventor.
. ^1. Its peculiar features consist m-the featheringa «ion of the paddles, and the application-if the balr‘ s m connection with them toadjust *eir 6^0^ascent upon the abutments at each revolution, byheated rotary concussions are avoided.
98 , Bennie,'
ana of a stone bridge proposed for unions
S ,l UWted t0 the Committee of the House of Commons
total 46 ‘ Total length, 827 feet; n "r ber w m&dle” tal Norway , 708 feet. Spans of arches.—midde
100 V 130feet i two arches, each 120 f eet; i I Thlmesliil feet; two arches, 95 feet He>gh ab w Iach 25water:—:middle arch, 27 feet; two arches, each 2
}’ , t , wo arches, 23 feet; two arches, 20 teet.
len;^ odel of a bridge proposed for Westminster Total
», 752 feet; number of arches, 5; total wateiwa*fe« feet - Middle arch, 150 feet; two side a I®hes>wn i Uvo s ’ de arches, 130 feet. Height above, tidala^l a W—middle arch, 27 feet 6 inches; two side, e f’ 25 feet; two side arches, 24 feet. . t
N 3 - Model of a bridge proposed for WestminsterNumber of arches, 7 ; spins, each 100 feet; height abovena mes high water, 26 feet. , „
.-*• ^, o4el °f a bridge recently constructed over the
the back-water and increase the efficiency of
Length, 525 feet; number ofspans, each 80 feet; versed
way, at Val St. Lambert,arches, 5; width, 26 feet;sine, 10 feet.
5. Model for a bow and string girder bridge, proposedto carry the Prussian railway over the Rhine at Cologne,agreeably to the programme of the Prussian Government.Span of each opening, 572 feet; span of drawbridge,96 feet, by George Banks Kennie, jun.
6. Model of a design of a Harbour of Refuge for Dover,submitted to the Commissioners, by the same.
99
The Commissioners of Northern Lighthouses,Edinburgh —Proprietors. Mr. Alan Stevenson ,Engineer.
Revolving dioptric apparatus of the first order (sameas that at Skerryvore). This apparatus consists of twoparts. The principal part is a right octagonal hollowprism, composed of eight large lenses, which throw out apowerful beam of light whenever the axis of a single lenscomes in the line between the observers and the focus.This occurs once in a minute, as the frame which bearsthe lenses revolves, in eight minutes, on the rollers placedbeneath. The subsidiary part consists of eight pyramidallenses, inclined at an angle of 50° to the horizon, andforming together a hollow truncated cone, which restsabove the flame like a cap. Above these smaller lenses(which can only be seen by looking from below) are placedeight plane mirrors, whose surfaces being inclined to thehorizon at 50° in the direction opposite to that of thepyramidal lenses, finally cause all the light made parallelby the refraction of these lenses to leave the mirror in a