398 Intelligence and Miscellaneous Articles. 



tungstate of soda is fused in a Hessian crucible with excess of pure 

 chloride of calcium at a moderate red heat, and the mass when cold, 

 washed with water. The salt is then left, forming a heavy, very- 

 crystalline, sparkling powder, in which the separate crystals are 

 easily distinguishable by a simple lens. By using some pounds of 

 the material?, we might certainly succeed in obtaining crystals so 

 large that their form might be distinguished by the naked eye. 

 Even with a magnifying power of 45 diameters, this crystalline 

 powder may be seen to consist of clear, very shining and sharp cry- 

 stals, many of which appear to be true square octohedra, but most 

 of them are combinations with many facets. Some of the former 

 were sufficiently large to be measured by the goniometer. I found 

 the angle of the basal edges of the octohedra =130° 20' 30", thus 

 agreeing with the corresponding angle of the compound occurring as 

 a mineral. 



The specific gravity of this artificially prepared Scheelite I found 

 to be =6*0759. That of the natural is given as 5*9 to 6*2. 



With this agreement in form and density, an analysis was hardly 

 requisite. However, I have also made this, by heating the finely 

 powdered salt with carbonate of soda, as it has been shown, that, 

 although acids separate yellow tungstic acid from it, it is only im- 

 perfectly decomposed by them. The lime was 19-58 per cent. 

 Hence the loss considered as tungstic acid amounted to 80*42 per 

 cent. The theoretical composition is 



CaO 19-45 



WO 3 80-55 



Annal. der Chem. u. Pharm. Bd. 81, Heft 2. 



ON THE GREEN COLOURING MATTER OF PLANTS, AND ON THE 

 RED MATTER OF THE BLOOD. BY F. VERDEIL. 



The green matter which can be extracted from the majority of 

 plants by means of alcohol or aether was considered as a pure homo- 

 geneous organic substance, and received the name of chlorophylle, 

 or green resin of plants. 



1 have discovered that this green resin is a mixture of a perfectly 

 colourless fat capable of crystallizing, and of a colouring principle 

 presenting the greatest analogies with the red colouring principle of 

 the blood, which however had never yet been obtained in a com- 

 pletely pure state. 



To isolate it, I precipitate a boiling solution of chlorophylle 

 in alcohol by a small quantity of milk of lime. The solution be- 

 comes colourless; the alcohol retains the fat, whilst the lime precipi- 

 tates all the colouring matter. This is separated from the lime by 

 hydrochloric acid and aether, which dissolves the green matter, 

 forming a coloured stratum at the top of the liquid. By evaporating 

 the aether, the colouring matter is obtained in a state of perfect 

 purity. — Comptes Rendus, Dec. 22, 1851. 





