82 iScientifio Intelligence, 



made in the presence of potassium cyanide. Many of the separa- 

 tions must be repeated in order to attain completeness. The 

 peroxides dissolve with great readiness in a mixture of nitric or 

 hydrochloric acid and hydrogen peroxide, the latter reagent act- 

 ing in this case as a powerful reducing agent. A serious difficulty 

 with this method arises from the presence of imj)arities, especially 

 silicic acid, in commercial hydrogen peroxide. The reagent can, 

 however, be obtained in a pure condition by distillation, accord- 

 ing to WolfFenstein's method, under diminished pressure. — 

 Zeitsehr. anorg. Ghem.^ xii, 134, etc. h. l. w. 



4. The use of " heavy solutions " in the examination of com- 

 mercial fertilizers. — Thoulet's solution, which has been so exten- 

 sively used by mineralogist?, has been applied by A. P. Bryant 

 to the separation of mineral phosphates from phosphates existing 

 in the form of bone, tankage, etc. Heretofore there has been no 

 means of distinguishing the cheaper " rock phosphates " from the 

 " organic phosphates," which are undoubtedly more readily avail- 

 able as food for plants, as they occur in prepared fertilizers as 

 sources of " insoluble " phosphoric acid. The author uses a solu- 

 tion of specific gravity 2*26, and gives the following table of the 

 specific gravities of substances commonly occurring in the mate- 

 rials under consideration : 



Bone and other organic matter, less than 2*0 



Gypsum 2*3 



Aluminium phosphates ._ above 2 -3 



Iron phosphates _ _ about 2 "6 



Silica _ _ 2-65 



Calcium phosphates 2-9 to 3*55 



Fluorite _ _ „. 3'2 



The separation is applied after treatment with water and dry- 

 ing, but before extraction with ammonium citrate. The simple 

 apparatus recommended by the author consists of a plain glass 

 tube about 1-3°"^ in diameter and 20^™ long, which is attached by 

 means of a short piece of rubber tubing to a tube of the same 

 diameter about 7°™ in length and closed at the end. The material 

 is placed in this apparatus with the heavy solution, and, after 

 corking, is thoroughly agitated. After the liquid has become 

 perfectly clear the rubber tube is closed with a pinch-cock and 

 the two portions are washed and submitted to analysis. A num- 

 ber of test-experiments, made with mixtures of known origin, 

 gave extremely satisfactory results. — Jour. Am. Ghem. /Soc, 

 xviii, 491. H. L. w. 



5. The action of nitric acid upon potassium cohalti-cyanide. — 

 In attempting to produce compounds analogous to the nitroprus- 

 sides by the action under consideration, Jackson and Comet, 

 while failing in this attempt, have obtained an interesting, new 

 class of salts. By long-continued boiling of potassium cobalti- 

 cyanide with strong nitric acid, the liquid gradually became dark 

 red and finally suddenly changed to a semi-solid gelatinous mass. 



