COORONGITE 907 



sand, and therefore answers exceedingly well for making concrete, with from one- 

 seventh to one-eighth part of lime. The best mode of making concrete, according to Mr. 

 Godwin, is to mix lime, previously ground, with the ballast in a dry state ; sufficient 

 water is now thrown over it to effect a perfect mixture ; after which it should be turned 

 over at least twice with shovels, or oftener ; then put into barrows, and wheeled away 

 for use instantly. It is generally found advisable to employ two sets of men to perform 

 this operation, with three sets in each set, and they repeating the process, turn over 

 the concrete to the barrow-men. After being put into the barrows, it should bo at 

 once wheeled up planks so raised as to give it. a fall of some yards, and thrown into 

 the foundation, by which means the particles are driven closer together, and greater 

 solidity is given to the whole mass. Soon after being thrown in, the mixture is ob- 

 served usually to be in commotion, and much heat is evolved, with a copious emission 

 of vapour. The barrow-load of concrete in the fall spreading over the ground will 

 form generally a stratum of from 7 to ft inches thick, which should be allowed to set 

 before throwing in a second. 



Another method of making concrete, is first to cover the foundation with a certain 

 quantity of water, and then to throw in the dry mixture of ballast and lime. It is 

 next turned and levelled with shovels ; after which more water is pumped in and the 

 operation is repeated. The former method is undoubtedly preferable. In some cases 

 it has been found necessary to mix the ingredients in a pug-mill, as in mixing clay, 

 &c., for bricks. For the preparation of a concrete foundation, as the hardening should 

 be rapid, no more water should be used than is absolutely necessary to effect a perfect 

 mixture of the ingredients. Hot water accelerates the induration. There is about 

 one-fifth contraction in volume in the concrete, in reference to the bulk of its ingre- 

 dients. To form a cubical yard of concrete, about 30ft. cube of ballast and 3| ft. cube 

 of ground lime must be employed, with a sufficient quantity of water. 



Several other methods have been adopted by builders and engineers : these, however, 

 involve the same principles and general condition ; a detail of them is, therefore, un- 

 necessary in this work. The reader desiring information is referred to works espe- 

 cially devoted to engineering and building. See HYDRAULIC LIME. 



CONDY'S DISINFECTING SOLUTION. A solution of an alkaline man- 

 ganate, or permanganate. See MANGANATES and DISINFECTANTS. 



CONFECTIONERY. See SWEETMEATS. 



CONGELATION. (Eng. andFr. ; Gefrierung, Ger.) The act of freezing liquids. 

 The processes employed are chiefly chemical, but some are mechanical. These will have 

 further attention under the heads FREEZING MIXTURES, ICE, and IOE MANUFACTURE. 



CONXCHAXiCITE. An arsenate and phosphate of copper found in Andalusia. 



CONIFER2E. The natural order of cone-bearing plants, including some of the 

 most important trees, such as all kinds of fir, cedar, juniper, pine, cypress, &c. 



CONIINE. C 16 H I5 N (C 8 H 15 M"). A volatile base found in hemlock (Conium 

 maculatuin). It is supposed to be the cause of the poisonous properties of that plant. 



CONIIVIA. A fragrant resin used for making pastiles. It is extracted from the 

 Hyawa, or incense tree, which grows in British Guiana. 



COITITTM. Conium maculatum. Spotted Hemlock. The celebrated Athenian 

 state poison by which Socrates and Phocion died. 



COORONGITE. Under this name a peculiar substance has recently been 

 imported from South Australia. It resembles caoutchouc in many of its physical 

 properties, and has been called by some authorities mineral caoutchouc or Elaterite ; 

 it seems, however, to be essentially different from that substance, and is probably a 

 product of vegetable origin. It is found in thin layers spread over the surface of the 

 ground in a sandy plain in the district known as the Coorong, in South Australia. 



Coorongite is a dark brown elastic substance, which exhibits under the microscope 

 a cellular structure interwoven with fibres. It does not vulcanize with sulphur. By 

 destructive distillation it evolves gaseous products ; and oils and acetic acid may be 

 obtained by condensation. According to an examination in the Colony, by Mr. 

 G. Francis, it is capable of being resolved into two substances: (1) a soft, semi-fluid 

 balsam, of an olive-green colour, insoluble in water, mineral acids, absolute alcohol, 

 and wood-naphtha, but soluble in ether, chloroform, benzole, turpentine, and essen- 

 tial oils ; (2) a tough, pulverulent, elastic substance, combustible, but insoluble in any 

 of the above-named menstrua. The specific gravity of Coorongite is 0'98 or 0'99. 

 An analysis by Dr. Bernays yielded : 



Volatile matter 97'190 



Fixed carbon 1-005 



Ash 1-790 



99-985 



