BABINGTONITE 279 



actual magnetic azimuth : and as we know the azimuth calculated from the N. and 

 8. line, the variation of the needle is readily found. 



AZOBENZENE, AZOBENZIDE, or AZOBEXTZOXi. C 24 H" 1 N- (C 12 H 10 Iir 2 ). 

 A peculiar substance formed by acting with an alcoholic solution of potash 

 upon nitrobenzole, or, as it is sometimes called, artificial oil of bitter almonds. 

 It' nitrobenzole, dissolved in alcohol, with the addition of solid potash, bo distilled, 

 a complex and by no moans well understood reaction occurs. The azobenzido 

 distils over mixed with aniline. The fluid treated with hydrochloric acid, to 

 dissolve the aniline, is passed through a wet filter ; the aniline salt passes through, 

 leaving the azobenzide as a red oil, which in a few moments solidifies into a mass of 

 rich golden-brown crystals of considerable size, even when working on a very small 

 quantity. The alcohol enters into the reaction, and oxalic acid is formed, which unites 

 with the potash. Four equivalents of nitrobenzole and two equivalents of alcohol 

 appear to yield one equivalent of azobonzide, two equivalents of aniline, four equiva- 

 lents of oxalic acid, and eight equivalents of water. See NITROBENZOLE. 



Azobenzene yields numerous derivatives. With fuming nitric acid it gives two 

 nitro-compounds ; viz,, nitroazobonzide and binitroazobenzide. Azobenzide, treated 

 with sulphide of ammonium, yields an alkaline called benzidine, C 24 H I2 N 2 (C^H^N 2 ). 

 C. G. W, 



AZOBENZOXDE. When bitter almonds are distilled, per descensum, an oil is 

 obtained ; if the latter be treated with ammonia, and the substance thus formed be 

 treated with ether, a white powder remains, which is probably impure hydroben- 

 zamide. C. G. W. See ' Watts's Dictionary of Chemistry.' 



AZOBENZOYXiE. A substance formed simultaneously with hydrobenzamido 

 and benzydramide, when oil of bitter almonds is treated with ammonia. C. G. W. 



AZOTE. An old name for NITKOGEN. 



AZOTISED, said of certain vegetable substances, which, as containing azote, 

 were supposed at one time to partake, in some measure, of the animal nature. The 

 vegetable products, indigo, caffeine, gluten, and many others, contain abundance of azote. 



AZURE. This term was applied by Pliny to the blues of the ancients. ' Cseru- 

 leum, or azure, is of three kinds : the Egyptian (artificial) ; the Scythian (natural), 

 which is inferior ; the Cyprian, the best.' Theophrastus, also Pliny. Girardin, 

 writing of the ancient colours, says, ' This azure, which has thus endured abovo 

 1,700 years, may be cheaply and easily made thus : 15 parts, by weight, of carbonate 

 of soda, 20 parts of opaque flints, and 3 parts of copper filings, are strongly heated for 

 two hours, and the mixture will result in a fine deep sky-blue.' The Egyptian blue, 

 or Alexandrian frit, is a pulverised blue glass ; it was once thought to contain cobalt, 

 but all analyses prove it to contain silicate of copper. 



The term Azure has been applied to smalts. See COBALT, SMALT, and ULTRA- 

 MARINE. 



AZURXXTE. See ANILINE-BLUE and ANILINE-GREEN. 



AZURITE. This term is now usually restricted to the blue carbonate of copper, 

 otherwise known as Chessylite. It is a mineral of fine blue colour, crystallising in 

 the oblique system. The old mines of Chessy, near Lyons, in France, were famous 

 for yielding groups of magnificent crystals of this species. It is also found in the 

 shallow workings of many other copper mines, often associated with malachite, or 

 green carbonate of copper. Azurite contains, when pure, 55'16 per cent, of copper, 

 and hence forms a valuable ore. It has also been used as a blue pigment, though too 

 liable to turn green, the absorption of carbonic acid readily converting it into 

 malachite. 



It is right to remark that the term Azurite has also been applied to certain other 

 blue minerals, such as the phosphate of alumina and magnesia, usually known as 

 Lazulite, and even to the lapis lazuli. 



The want of agreement between mineralogists leading them to adopt names 

 independent one of the other (names frequently taken from some locality in which 

 the writer knows the mineral to be found) produces great confusion, and retards the 

 progress of knowledge. 



BABBIT'S METAXi. An alloy which, from its smoothness of surface, is called 

 an anti-attrition metal. It is composed of 25 parts of tin, 2 parts of antimony, and 

 $ a part of copper. 



BABIZiTCTOZriTE. An anhydrous silicate of iron and lime, found in small, 

 greenish-black, doubly-oblique crystals, at Arendal, in Norway. A fibrous variety, 



