CON
188
CON
already alluded, and states that he had again examined thewall at Woolwich, and found the interior as hard as could bewished. Those parts, however, of the concrete facing, whichwere exposed to the mechanical action of the water, wereinjured by it; and therefore, though recommending concretebelow low-water mark, he was bound to admit that it wasnot adapted to those situations where it must be exposed tosuch action.
1 The specific gravity of concrete, as compared with that ofother materials, is as follows ;—
Concrete weighs about 140 lbs. to the cubic foot
Granite. 160 to 170
Portland stone. 150.
We must refer to the report itself for'more detailed infor-mation on this subject, only adding the conclusion come toby the committee, that “ there is not sufficient experience ofthe use of concrete to warrant its adoption for the facesof works to be constructed in the sea.”
The French engineers have made use of beton in many ofthe extensive works on the continent; beton sets very; rapidly under water, and attains, after a time, a very con-j siderable degree of hardness. M. Milet de Montville having. | filled a chest containing 27 cubic feet of beton, sunk it inI the sea, where it remained during two months, after which! it was drawn up, to ascertain the consolidation it had: acquired. On inspection it was found to be converted into| so compact a body, that more difficulty was experienced in! ! separating its parts, than those of a block of hard stone.The best manner of compounding the beton, according to: M. de Montville, is as follows:—“ Take twelve parts ofpuzzolana, (terrasse de Hollande, or cendre de Tourney,)
; of which form a circular wall of five or six feet in diameter,on which place six parts of sand, well sifted, free fromearthy matter, and evenly spread. Fill the interior of thiscircle with nine parts of quick-lime, well calcined, and pul-verized with an iron beetle; and to cause it to slack morequickly, (in maritime works) throw on sea-water in smallquantities, stirring it from time to time with an iron spatula.As soon as it is reduced to a paste, incorporate the puzzolanaand the sand. The whole being well mixed, throw in thir-j teen parts of unhewn stone, and three parts of iron dross,well pounded. If this latter ingredient cannot be obtained,sixteen parts of rough stones or pebbles must be added, of asize not larger than a pullet’s egg. Let this composition bei well amalgamated for the space of an hour, after which it
j must be left in heaps to coagulate ; for this purpose the space
; of twenty-four hours will be sufficient in summer or in warm
; climates, but in winter it often requires the space of three or
| four days. Observe to keep it protected from the rain, and
j not to use it until it has sufficiently hardened to require
breaking with a pickaxe.”
j The method of using the beton is either in blocks, or by; means of a coffer or chest filled with the composition, loweredj to the required depth, and there emptied.
I CONCRETION (from the Latin , concresco) the act of' concreting; the process by which soft or fluid bodies becomethick, consistent, solid, or hard; the act of uniting, by1 natural process, the small particles of matter into a mass.
The word is used indifferently for induration, condensation,
! congelation, or coagulation.
CONCURRING, or Congruent Figures, or Solids,such as will cover each other exactly, or will fill the samei space. All plane figures will do this, when their correspond-I ing angles and sides are equal.
! CONDUIT (from the French ) a canal, or pipe, for thej conveyance of water, or other fluid matter; an aqueduct.
of
The earth is full of natural conduits, for the P a9S£ ^jjicbwaters, which give rise to springs, and of vapoursgenerate metals and minerals. . s ton e >
Artificial conduits for water are made of lead, cast ir° n >potters’ earth, &c. See Plumbery. c0 p-
Also the reservoir or erection where the waters iU ® 0 fducted and distributed for use. Previous to the forma , nthe present water-companies, these conduits were freq uthe different parts of London , and were the only me* 1which the inhabitants were supplied with water ; * t i,econduit erected was one near Bow Church, Cheapsid e >* gr g 8reign of Henry III. ; and among the latest was one o ^dimensions, erected in 1655, at Leadenliall, which s ' ^likewise for an ornamental fountain. Conduits of j gS tab'of an early date were usual in our large ecelesiastica
lishments, and where cloisters existed, there was
one in the centre of the quadrangle; which custom ia r jjury>observed in the quadrangle of S. Augustine’s, Cant ^lately erected, where the conduit, of excellent desig D >
beef
an imposing feature.
The first attempt to carry water into the houses - ,was made by Peter Morris, a.d. 1582, who establis), T
of IT
: doO
tb*
-- --,--, .. .... - .j JjoD
waterworks constructed under two of the arches ol u Q tA ce‘don Bridge, but their supply extended only as far as gcte dchurch-street; soon after, in 1594, similar works werenear Broken Wharf, which supplied the houses in u e ul itdand around S. Paul’s, as far as Fleet-street. It was no ^ a
the reign of James, that any enterprise of this
iff
large scale was undertaken, when the formation of 'River was commenced by Sir Hugh Middleton in l 0completed in 1613. w t"'°
CONE (from the Greek, kwvoc) a solid, bounded ■surfaces, one of which is a circle, called the base, and j, a
. ; and ot _ c ji~
a convexity, ending in a point, called the vertex;
the
nature, that a straight line applied to any point m , V 'i :cumference of the base and to the vertex, will comm
th
the convex surface.
, tO
th e
The straight line drawn from the centre of the havertex of the cone, is called the axis. b 95 ?’
When the axis of the cone is perpendicular to jt
the cone is called a right cone, but when otherWcalled an oblique cone. , 9 gct' oIJ
If a cone be cut by a plane through its vertex, twill be a triangle. . s ec t ‘° ,>
If a cone be cut by a plane parallel to its base, tnwill be a circle, or similar to the base. r tjofl c .
*If a cone be cut by a plane, so as to make the a cir cle ’ °off similar to the whole cone, the section will be _
similar to the base. pa s3lI, 5
If a cone be cut by a plane parallel to a P‘ an rod uC Lthrough the vertex, meeting the plane of the off B
without, the section is an ellipsis, except the p 9rt {
similar to the whole cone, as in the last position. c o» t9If a cone be cut by a plane parallel to a plan ewith its side, the section will be a parabola. . 0ll of ^If a cone be cut by a plane parallel to a seC ^jji b econe passing through the vertex, the sectionhyperbola.
Every cone is one-third part of a cylinder ot 11 0 f e<l ‘and altitude (Euclid. , b. xii., prop. 10.), and ®° n jpj., b- ^ g faltitudes are to each other as their bases p art
prop. 11) ; therefore any cone whatever is thea cylinder of equal base and altitude with the con g ’ eC tofThe curved surface of a cone is equal to the 0 fcircle, the radius of which is equal to the slantm*, c ; r ciicone; and the arc-line of the sector is equal toference of the base of the cone.