cox 



CON 



stone chippings or ballast cemented 

 together through the medium of lime 

 and sand, usually employed in ma- 

 king foundations where the soil is 

 of itself too light or boggy, or other- 

 wise insufficient for the reception of 

 the walls. The essential quality of 

 concrete seems to be, that the mate- 

 rials used should be of small dimen- 

 sions, so that the cementing medium 

 may act in every direction round 

 them, and that the latter should on 

 no account be more in quantity than 

 is necessary for that purpose. Ar- 

 chitects and engineers have much 

 varied the proportions of lime and 

 sand used. If the lime, which should 

 be fresh and ground to powder, be 

 good stone Ume, it will bear three or 

 four times its measure by bulk of 

 sand. These and the ballast or gal- 

 lots, as the stone chippings are called, 

 should be thoroughly turned over and 

 mixed together. If the foundations 

 be wet, the mixture will want very 

 little if any water ; indeed, some- 

 times the ballast only is wetted, and 

 then covered over with the lime and 

 sand. It is then filled into the bar- 

 rows, and run on to be dropped from 

 a stage into the foundations. This 

 latter operation should be performed 

 at as great a height as possible above 

 the level of the trench, in order that 

 the whole of the different particles 

 of the composition may be compress- 

 ed together so as to occupy the least 

 possible space. The stones employ- 

 ed should not exceed the size of a 

 common hen's egg. The mass very 

 quickly sets and becomes extremely 

 hard. On the top of it, which is kept 

 as level as possible, a tier of stone 

 landings is laid, and very often 

 throughout the length a chain of tim- 

 ber is buried in the footings, whose 

 durability is requisite only while the 

 work is settling; over the landings 

 and timber thus laid, the latter, it is 

 to be observed, occupying but a very 

 small portion of the thickness of the 

 footings, and quite buried in them, 

 the walls are carried up. — (See Daty 

 OH Artificial Foundations, and Toltcn 

 on Mortars, Cements, &C.) 



CONDENSATION. The render- 

 P2 



I ing a body more dense, most com- 

 monly applied to the conversion of 

 vapour into the fluid form. 



CONDENSER. Any machine by 

 which the compression of gas, &,c., 

 can be effected. 



j CONDITION. In horsemanship, 

 the health and good appearance of a 

 horse or other animal. 



CONDUCTOR. In physics, any 

 substance which allows the passage 

 of heat, light, or electricity is said to 

 conduct it. 



CONDYLE (from Kovdv, a cup). 

 The rounded ends of the long bones. 



CONFERVA. An extensive fam- 

 ily of small water weeds, forming the 

 green slime on stagnant waters. 

 They nourish innumerable insects 

 and animalcules. 



CONGELATION. The act of 

 passing into the state of ice or other 

 solid forms from the fluid. 



CONGESTION. In farriery and 

 medicine, an increased accumulation 

 of blood or other fluid in any part. 

 It is to be relieved by bleeding, cup- 

 ping, leeches, or counter irritation. 



CONGLOMER.\TE. In geology, 

 a compound stony mass containing 

 pebbles, &c., cemented together by 

 iron, calcareous or other matter. 



CONIC. Relating to a cone, small- 

 er at one end than the other. 



CONIFER^E. Trees bearing 

 cones, as the pines, firs, cedars, ikc. 

 The wood of all is useful, and they 

 grow usually upon poor soils. 



CONIROSTERS. A tribe of birds 

 with strong conical bills, as crows 

 and finches. 



CONTU.M. The genus containing 

 hemlock, which see. 



C O N N I V E N S. In botany, any 

 covering or arrangement by which 

 the parts of a plant or flower are hid- 

 den ; as the flowers of the fig by the 

 connivent receptacle. 



CONSERVATORY. In horticul- 

 ture, a glazed structure, in which 

 exotic trees and shrubs are grown 

 in a bed or floor of soil. It is distin- 

 guished from an oranger>' by its hav- 

 ing a glazed roof, while that of the 

 I latter is opaque ; and from a green- 

 , house, by the plants being planted in 



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