Volume 1

The chemical pocket book, or Memoranda chemica, arranged in a compendium of chemistry / By James Parkinson, Hoxton.

  • James Parkinson
Date:
1809
Catalogue details

Licence: Public Domain Mark

Credit: The chemical pocket book, or Memoranda chemica, arranged in a compendium of chemistry / By James Parkinson, Hoxton. Source: Wellcome Collection.

    305/424 (page 281)
    This mould lie considers as formed of all those elements ot the vegetable which have not been expended in the formation of water and of carbonic acid. It is found to contain a greater proportion of carbon than belong to the plants from which it proceeds: this superabundance of carbon depending on the consumption of the oxygen and hydrogen, in the formation ot water.—Ann. de Chim. Cali. 150. From this property, which the mould possesses, of absorb- ing oxygen, results much of the advantage proceeding from tillage, since by frequently changing the surface of the earth, the process must necessarily be accelerated. The tilled earth thus absorbing oxygen from the air, leaves the air at the surface in possession of more than its common proportion of nitrogen.—Hence, on the Alps the atmospheric air contains more oxygen than that of the warmer plains, the snow prevent- ing the contact of the air with the earth, and of course this absorption of oxygen. The agriculturist will derive the greatest advantage from the careful study of a paper by Mr. Davy, on the Analysis of Soils, as connected with their improvement, in ]\'icholson’s Journal. October, 1805. ' BITUMINOUS SUBSTANCES. NAPHTHA is a transparent white, or yellowish white sub- stance, exceedingly light, and fluid as water. It feels greasy, has a penetrating odour, and burns with a light flame, leaving scarcely any residuum. It is insoluble in spirits of wine, and passes over intirely in distillation; it is thickened, but not inflamed by nitric acid. Petrol, or Petroleum, is a brown semi-transparent sub-