221 



Tribasic Acids and Cyanogen Acids. 



Note. This specimen is part of the racetnic acid produced by Keutner 

 between 1820 and 1824. It was exhibited in 1851 at the International 

 Exhibition, and was purchased at its close by Professor Redwood, by whom 

 this specimen were presented to the Society. For distinctive characters 

 of the crystals, see Fownet, Chemittry, p. 736. 



CAMPHORIC SERIES, C a Eva-tOi 



530. CAMPHORIC ACID. H a Cj H u 4 . 

 a. Crystalline powder. 



PHTHALIC SERIES. C B H to _,,,04. 



537. PHTHALIC ACID. H 3 C 8 H 4 V (Orthophthalic AciJ, Alizaric, 



or Naphthalic Acid.) 

 a. Pale yellowish powder. 



TRIBASIC ACIDS. 



TRICARBALLYLIC SERIES. C n H 2 n_ 4 O r j 



538. CITRIC ACID. H 3 C a H 6 7 . 



a. Crystals. 



ACONITIC SERIES. C n H2n_Os. 



539. ACONITIC ACID. H 3 C 8 H 3 3 . (Citridic Acid, Equitetic Acid.) 



a. Pale fawn-coloured powder. 



MECONIC SERIES. C^H^.uOr, 



540. MKCONIC ACID. H 3 C 7 H 7 . 



a. Impure, in acicular crystals. 



b. Pure, in acicular crystals. 



ACID CYANOGEN COMPOUNDS. 



541. HTDROCTANIC ACID. HCy. (Hydrogen Cyanide, Prussic Acid.) 



a. Colourless liquid. (Scheele's Prussic Acid.) 



b. Colourless liquid. (Acidum Hydrocyanicum dilutum, 



S.P.) 



Note. Specimen a contains 5 per cent, of anhydrous acid, and speci- 

 men b, 2 per cent. 



542. HTDROFERROCTANIC ACID. H 4 Ft" Cy 8 . (Hydrogen Ferrocy- 



anide.) 



a. White powder. 



543. CTANURIC ACID. C 3 H 3 N 3 3 . 



a. Small prismatic crystals. 



