230 ANNUAL OF SCIENTIFIC DISCO VERY. 



by the addition of tin, lead, and copper. The folio wing proportions are recoL 

 mended : 89 to 93 parts of zinc, 3 to 6 parts of tin, 2 to 4 parts of lead, and 

 2 to 4 parts of copper. 



DETECTION OF PHOSPHOKIC ACID IN" EOCKS. 



The solution of phosphate of lime in fused chlorides of sodium, and its 

 separation on cooling, furnish an excellent means of detecting minute quanti- 

 ties of phosphoric acid in rocks, etc. For this purpose the powdered sub- 

 stance is heated with 50 per cent, of chloride of sodium, which, when the 

 substance is tolerably fusible, separates from the silicates as an upper layer. 

 When the substance is not fusible, the chloride of sodium remains partially 

 mixed with it, in cavities distributed throughout the mass, and presenting 

 after the solution of the chloride a remarkable similarity to the vesicular cav- 

 ities of amygdaloid. The small crystals of apatite generally project like hairs 

 from the surfaces of the partially dissolved mass, and being soluble hi very 

 dilute hydrochloric or nitric acid, they may be collected by that means and 

 estimated. The author has in this way detected phosphoric acid in green- 

 stone belonging to the primitive and transition formations of Scotland : in 

 the greenstone occurring as boulders in the more recent formations ; in that 

 of the trap formation of Greenland ; in the basalt of Steinheim ; in a coarse 

 granular basalt or lava from Iceland ; in three varieties of gneiss and granite 

 from Bornhohn, and in two varieties of mica schist. From one Bornholm 

 granite, remarkably fine and distinct crystals of apatite were obtained. The 

 observation made some years ago by Fownes of the presence of phosphoric 

 acid in rocks thus gains further confirmation, in addition to the testimony of 

 Swanberg and Struves. Correspondent Edinburg Journal 



ACTION OF WATER AND AIR ON BASALT. 



Bensch having ground a quantity of basalt to a fine powder with water on 

 a porphyry slab, left it for some months in a beaker glass, covered with paper. 

 At the end of that time it was found to have been converted into a mass so 

 hard as to require a smart blow of a hammer to break it. Its fracture was 

 similar to that of the natural basalt, and the interior consisted of a black core, 

 having a waxy luster, and surrounded by a less compact gray mass. By 

 longer exposure to the air, an efflorescence of carbonate of potash appeared 

 on the surface, and T8 per cent, was extracted by water. The specific 

 gravity of the basalt was 2 "8 8 7, and after extraction of the carbonate of 

 potash, the internal portion of the altered basalt had a specific gravity of 

 2-1588; that of the external portion was 2-0423. There is no doubt that a 

 hydrate must have been formed in this case, and the observation may serve to 

 throw some light on the changes which take place in the weathering of rocks. 

 Annalen der Ghimie und Pharmacie, v. xci., p. 234. 



SEPARATION OF BROMINE FROM IODINE. 



Balard's process gives a method of recognizing traces of iodine, and at the 

 eame tune separating it from bromine, with which it is so often associated. 



