187 



in ether, does not precipitate glue, coloui's chloride of iron dark- 

 green ; is not precipitated by tartarated antimony and acetate of 

 lead, bxit is so by sub-acetate of lead, and by a solution of acetate 

 of lead in alcohol. The aqueous solution throws down a red 

 powder (quinova-red) when allowed to stand at the air. 



C[uinovic Acid=C24 H19 O5. Found in the leaves of Pinus 

 sylvestris, and in the green parts of Thuja occidentalis and many 

 other coniferce. Boil with alcohol of 40%, remove from the ex- 

 tracts the alcohol by evaporating, mix the remnant with water, 

 dissolve the gi"een i-esinous deposit in alcohol of 40%, precipitate 

 the solution with alcoholic acetate of lead, throw down the excess 

 of lead in the filtered liquid with sulphuret of hydrogen, filter and 

 distil the alcohol; dissolve the remaining i-esin in very diluted 

 potash-ley ; thi'ow down the resins by chloride of calcium, saturate 

 the filtered liquid with hydrochloric acid, which precipitates pale- 

 yellow flocks of Quinovic acid. These have to be re-dissolved in 

 very diluted potash-ley, purified by treating with animal charcoal 

 and ^precipitated with hydrochloric acid. — White or slightly 

 yellowish, brittle mass, friable to a highly electric powder. 



RacemiC Acid = C4 H2 O5 -1- HO + Aq. Observed as yet 

 only in cream of tartar, associated with tartaric acid. The isola- 

 tion and pui'ification of this acid is identical with that of tartaric 

 acid. It is distinguished from the latter by the klinorhomboidal 

 form of its crystals, by its tendency to effloresce at the air, and by 

 losing one equivalent of water at 100°, and then having exactly 

 the same composition as tartaric acid. Its aqueous solution be- 

 comes turbid by sulphate of lime and the deposit obtained by lime 

 water is insoluble in chloride of ammonium. 



Rape-Oil. Obtained by pressing the seeds of several varieties 

 of Brassica olerac'ea; is brownish-yellow, originally mild, assumes 

 by keepinga nauseous odour and taste, is of 0912 to 0*920 density, 

 thickens below, 0°. Not drying. 



Raspberry Camphor. Obtained by distillation with water from 

 the fruits of Rubus Idseus. — Small, white lamina3, either lighter 

 or heavier than watei', soluble in water, alcohol, ether, and alka- 

 lies. 



Ratailllia Tannic Aci(l=Cis Hs O7. In the Ratanhia-root 

 and in the bark of the root of Savanilla-Ratanhia (from Krameria 

 triandra and K. Ixina). Exhaust with ether, treat the ethereous 

 extract with alcohol and evaporate the solution. — Ruby-red, 

 amorphous, permanent at the air, of a bitter and astringent taste, 

 of acidulous reaction, fusible by heat, dissolves in water, alcohol, 

 ether; colours and precipitates chloride of iron dark-green, precipi- 

 tates glue, not tartarated antimony; becomes decomposed with 



