DEPHLOGISTICATED 13 



attended with the flying asunder of their parts, made by several minerals and salts 

 when heated. Sulphate of baryta, chloride of sodium, calcareous spar, nitrate of baryta, 

 and several other bodies which contain no water, decrepitate most violently, separating 

 at the natural joints of their crystalline structure. 



DEFECATION. (Eng. and Fr. ; Klaren, Ger.) The freeing from dregs or 

 impurities. 



DEFLAGRATION. (Eng. and Fr. ; Verpuffung, Ger.) A rapid combustion, 

 attended with much evolution of flame and vapour. When metals are burnt by elec- 

 tricity, they are said to undergo deflagration. 



DEFXiAGRATOR. A galvanic instrument for producing a rapid and powerful 

 combustion, introduced by Professor Hare. 



3>E XiAXNES. Properly, fine worsted fabrics. They are indeed figured muslins, 

 which should always be made of wool, but they are frequently made of mixed material. 



DEX.AWARXTE. A cleavable potash felspar, from Delaware County, Pennsyl- 

 vania. 



DEXiESSXTE. A ferruginous chlorite, usually occurring as a dark greenish coat- 

 ing in the interior of amygdaloidal cavities in trap-rocks. 



DEXiF or DEXiFT. A coarse species of pottery originally manufactured at Delft 

 in Holland, covered with a white stanniferous enamel or glaze. See POTTERY. 



DELIQUESCENT. (Zerfliessen, Ger.) Any solid which absorbs moisture from 

 the air spontaneously and becomes soft or liquid, such as potash, and chloride of calcium 

 is said to be deliquescent. 



DEXiPHXNlA. The poisonous principle of the Stavesacre (Delphinium Staphy- 

 sagria). 



DEXiVAUXXTE. A variety of Dufrenite, or hydrous phosphate of iron. 



DEMIDOFFXTE or DEMIDOVITE. A mineral mixed with malachite, 

 found at Nischne-Tagilsk in Eussia. It contains oxide of copper 33'14, silica 31'53, 

 magnesia 3,15, phosphoric acid 10'22, and water. 



DENDRXTES. Arborescent or shrub-like markings on rocks, commonly pro- 

 duced by oxide of manganese ; thus, the ramified patterns in Mocha-stones are den- 

 drites. Dendritic, a term applied to the branching forms of certain minerals, such as 

 native copper and native silver. 



DEMIT. Paper of a particular size is so called. Drawing demy is 15 inches by 20, 

 printing demy is 17f inches by 22 J. 



DENMARK SATIN. A stout worsted stuff used for ladies' shoes. 



DENSITY, the property of compactness in bodies, the closeness of their component 

 particles. The specific gravity of bodies is taken as a measure of their densities. See 

 SPECIFIC GRAVITY. 



DENTIFRICE. Tooth-powder for the purpose of cleansing the teeth. A variety 

 of preparations are recommended. The object being to remove acid incrustations 

 from the teeth, and to cleanse them from feculent matter, simple preparations of chalk 

 or magnesia are undoubtedly to be preferred. Occasionally charcoal may be used 

 with advantage, but the particles are usually too hard, and consequently they tend to 

 abrade the fine enamel-surface of the teeth. 



DENUDATION. (Denudo, to lay bare.) The carrying away by the action of run- 

 ning water or other agent, of the superficial solid materials of the land, by which the 

 character of the surface is altered, and the lower rocks often laid bare. 



DEODORISERS. Bodies which have the power of depriving fetid and offensive 

 effluvia of their odours. There appears to exist a general idea that these substances 

 are, all of them, equally disinfectants. No greater mistake can be made than to 

 suppose that because a preparation has the power of removing a disagreeable smell, that 

 therefore it has removed all the elements of infection or disease. See DISINFECTANT. 



To disguise unpleasant odours, fumigation is employed, many of the fragrant gums 

 are burnt and fumigating pastiles employed. It is also a common practice to burn 

 lavender and brown paper, but these merely overpower or disguise the smell ; they do 

 not in any way act upon the noxious effluvia. See PASTILES ; FUMIGATION. 



DEOXXD ATION. The act of removing oxygen ; thus, when oxide of iron is 

 heated with carbonaceous matter the oxide is deoxidised, and metallic iron reduced. 



DEPHXiEGMATXON. The process by which liquids are deprived of their 

 watery particles. It is applied chiefly to spirituous liquors, but is now obsolete, as 

 involving the alchemistical notion of a peculiar principle called phlegm. 



DEPHZ.OGXSTICATED, deprived of phlogiston, which was for a long period 

 after the time of Stahl regarded as the principle of levity and of combustion. It may 

 be regarded as synonymous with oxygenated. Others believe that Earth and Phlogis- 

 ton are those principles which are the constituent parts of all corporeal substances.' 



' It appears from all those experiments, that in each of them phlogiston, the simple 

 inflammable principle, is present,' f Thus much J see from the above-mentioned es- 



