AEG 



[34] 



AEG 



for measuring the density or weight 

 of any liquid. 



A'RFWEDSONITE. The name given by 

 Brooke, in honour of Professor 

 Arfwedson, to a mineral now 

 separated from hornblende, of 

 which it was wont to be deemed a 

 ferriferous variety. It occurs in 

 Greenland. Colour black; and 

 opaque. It contains above 35 per 

 cent of iron. 



A'RGAL. Crude tartar, as deposited 

 by vinous fermentation. 



ARGE'NTAL. (from argentum, Lat.) 

 Containing silver; combined with 

 silver. 



ARGENTIFEROUS, (from argentum and 

 fero, Lat.) Producing silver. 



ARGENTINA. A genus of fishes of 

 the order abdominales. 



ARGENTINE. Slate-spar; a mineral 

 of a lamellated, or slaty structure ; 

 a nearly pure sub-species of carbon- 

 ate of lime. 



A'RGIL. } argilla, Lat. ap^iXXos or 



A'RGILL. ) a/>ryt\oe, Gr. argille, Fr. 

 argilla It. See Alumine.) In 

 1754, Margraff showed that the 

 basis of alum is an earth of a 

 peculiar nature different from every 

 other ; an earth which is an essen- 

 tial ingredient in clays, and gives 

 them their peculiar properties. 

 Hence this earth was called argill ; 

 Morveau afterwards gave it the 

 name of alumina, because it is 

 obtained in the state of greatest 

 purity from alum. 



ARGILLA'CEOTJS. (argillaceus, Latin.) 

 Clayey; of the nature of argil; 

 containing argil. The rocks which 

 are termed argillaceous have been 

 all arranged into one suite, and 

 present the following gradation ; 

 clay slates, shale of the coal- 

 measures, shale of the lias, clays 

 alternating, in the oolite series, 

 and that of the sand below the 

 chalk ; and clays above the chalk. 



ARGILLA'CEOUS-SCHIST. Clay slate. 

 An indurated clay, or shale, common 

 to the fossiliferous and metamorphic 

 series. 



ARGILLIFEROUS. (from argilla and 

 fero, Lat.) Producing or yielding 

 clay. 



A'RGILLITE. Argillaceous-schist, or 

 clay-slate. Slate is a very ex- 

 tensive formation, composing entire 

 mountains in many alpine districts. 

 The prevailing colours are bluish, 

 or greenish grey : it has a silky 

 lustre. 



ARGI'LLOTTS. (argillosm, Lat. argilleux, 

 Fr . argilloso, It. ) Containing clay ; 

 of the nature or quality of clay. 



ARGONA'UTA. The Paper Sailor ; a 

 genus of animals ; class Yermes, 

 order Testacea. An involuted uni- 

 valve, both recent and fossil, the 

 spire turning into the opening ; 

 very thin, with a tubercular double 

 dorsal keel. There are several 

 species, but the most remarkable 

 one is the Argon auta Argo, or Paper 

 Nautilus. " Doubts still exist 

 whether the Sepia found within 

 this shell be really the constructor 

 of it, or a parasitic intruder into a 

 shell formed by some other animal 

 not yet discovered. Broderip, Gray, 

 and Sowerby, are of opinion, that 

 this shell is constructed by an 

 animal allied to Carinaria. BucJc- 

 land. 



Cuvier placed argonauta among 

 the subgenera of Sepia, and Dr. 

 M'Murtrie, in his translation, says, 

 " These mollusca are always found 

 in a very thin shell, symmetrically 

 fluted and spirally convoluted, the 

 last whorl so large that it bears 

 some resemblance to a galley, of 

 which the spine is the poop. The 

 animal makes a consequent use of 

 it, and in calm weather whole fleets 

 of them may be observed navigating 

 the surface of the ocean, employing 

 six of their tentacula as oars, and 

 elevating the two membranous ones 

 by way of sail. If the sea become 

 rough, or they perceive any danger, 

 the argonaut withdraws all its 

 arms, concentrates itself in its 

 shell, and descends to the bottom." 



