ACA 



SUPPLEMENT. 



ACT 



ACANTHOIDE, from aKavda, "a spine," 

 mineral occurring in whitish silky needles 

 In the Vesuvian lava of 1S21, and in dark 

 brown and reddish fibres in other lavas. 



ACANTHOPHIS, a genus of Australian 

 serpents belonging to the vipers, with a 

 peculiar horny sting-like spine at the ex- 

 tremity of the tail. 



ACANTBURUS, a genus of fishes with spiny 

 fins, and especially a powerful moveable 

 spine on each side of the caudal extremity, 

 capable of inflicting serious wounds. 



ACCUMULATION of Power, one of the ele- 

 ments for consideration in the construction 

 cf machinery, the efficiency of which depends 

 much on its power to resist the force which 

 its action does not relieve or give full effect 

 to, and which in consequence accumulates 

 against the machinery itself. 



ACERACE.E, a small order of polypetalous 

 exogens, of which the acer is a typical 

 genus. 



ACERA, or ACERANS, d /cepoj, without 

 a horn, a family of apterous insects without 

 antennae ; also a family of gasteropodous 

 molluscs without tentacles. 



ACERDESE, grey oxide of manganese. 



ACETAL, an inflammable liquid obtained 

 from the action of spongy platinum on 

 alcoholic vapour. It is colourless, and under 

 slow combustion is converted into acetic 

 acid. 



ACETAMIDE, a white crystallin" body, 

 soluble in water, obtained by the replace- 

 ment in ammonia of an equivalent of 

 hydrogen by acetyle. 



ACHMATITE, a variety of pistacite or lime 

 and iron Epidope found at Achmatowsk. 



ACUROITE, the colourless varieties of tour- 

 maline, from a xpota, without colour. 



ACOLLE, (from col, the neck, signifying 

 collared,) animals with collars are so described 

 in heraldry ; also two things joined together ; 

 or swords, spears, &c., placed saltire-wtw 

 behind the shield. 



ACONITIC Acid, or citridic acid, a crystal- 

 line acid body found in aconite, the ritrer 

 Equisetum, &c. : whence called also equisetic 

 acid. It is artificially procured from the 

 residue of the distillation of citric acid : hence 

 one of the above names. 



ACORACE*, the natural order of plant* 

 of which Acorus is the typical genus. 



ACRE fight, a single combat, engaged in on 

 the English and Scottish borders during the 

 period of border warfare. 



ACRIDIA, a family of orthopterous insects, 

 of which Acrydium, or Acridium, is the 

 typical genus. 



ACRODACTYLUM, the upper surface of 

 each digit in zoology. 



ACRODUS, a genus of fossil sharks with 

 large polygonal obtuse enamelled teeth at 

 the extremity of the jaw. 



ACROLEINE, an acrid volatile product of 

 the destructive distillation of fat oils, result- 

 ing apparently from the decomposition of 

 glycerine. 



ACROLITHOS, in the statuary of the 

 ancient sculptors, any statue in which the 

 drapery was made of wood, and the nude 

 portions of marble. 



ACROPODIUM, the upper surface of the 



ACETANILIDE, a solid crystalline body, en ti r e foot in zo'ology 

 soluble in hot water, obtained by replacing ACRO P O LIS, the citadel or upper town of 

 in aniline one atom of hydrogen by acetyle G k m d geueral i y tne portion first 



ACETIC Ether, a compound of acetic acid i bullt 



and ether with an odour like apples, obtained AC R OTARSIUM the upper surface of the 

 by distilling alcohol and oil of vitnol with I 



acetate of potash. It is a flavouring of 

 various wines. 



ACETINES, oily bodies prepared by com- 

 binations of acetic acid with glycerine. 



ACETONITRILE, a former name of cyanide 



tarsus in zoology. 



ACRYLE, the hypothetical radicle of the 

 hydride acroleine. 



ACRYLIC Acid, acroleine oxydized. 



ACTINISM, the effect produced by the sun's 

 rays or artificial light employed in photo- 



graphy, by which chemical decompositions 

 ud combinations result ; distinguished 

 rom the light-n<i-heat-giviug powers of the 



of methyle. 



ACETUREIDE, urea in which acetyle has 

 replaced hydrogen. 



ACETYLA, Diethylenia, or Acetylamine, an 



organic base obtained by the replacement of I AcrTNocRiNiTES, a sub-genus of eucri- 

 two double equivalents of hydrogen bytwo; nites w uh rows of angular plates articu- 

 of ethy lene in a double atom of ammonia. ' late(i ' b their e( ^ es 



ACETYLE, the hypothetical radical of, ACTINOGRAPH, an instrument constructed 

 acetic compounds composed of four atoms of b Mr Hunt for recording the variations in 

 carbon and three of hydrogen. C 4 1I 3 | the actiujc power of lae ,., rayg Jt is & 



ACETYLENE, one of the hydro-carbon fixed cylinir, covered with photographic 

 gases remarkable for containing the smallest paper, enclosed in a metal cylinder, which 

 proportion of hydrogen. I completes a revolution round it every 



ACHIEVEMENT, a shield of armorial bear- twenty-lour hours. The photographic paper 

 ings in heraldry, but more particularly the is exposed through a triangular opening in 

 hatchment, or funereal shield. the outer cylinder to the solar light, the 



ACHILLEINE, the bitter principle of opening being divided by fifty bars. 

 Actillea Millefolia. | ACTINOMETJW. an ingenious invention of 



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