Chemistry and Physics. 109 



6. On the analysis of some of the Sulphur Acids; by MM. Fordos 

 and Gelis, (Annates de Chim. et de Phys., Jan., 1848.)— The process 

 for the analysis of some of the lower sulphur acids, by means of chlo- 

 rine, is not only tedious but liable to error when the acids are readily 

 decomposed. The use of standard solutions having suggested itself to 

 the authors — they tried permanganate of potash and chlorid of gold 

 without success, but at last found every thing that could be wished in 

 the hypochlorites used as decomposing agents. 



All the lower sulphur acids, with the single exception of the hyposul- 

 phuric, are immediately oxydated by the hypochlorites, and an excess 

 of the reagent is not required. 



Dilute solutions of potash or soda saturated with chlorine — hypo- 

 chlorite of soda obtained by double decomposition or even solution of 

 chlorid of lime will answer for the reagent. Hyposulphite of soda, 

 being easily obtained in a state of purity, answers perfectly as a test of 

 the strength of the reagent — 1 part of this salt requires for its oxyda- 

 tion 114 of chlorine — the liquid containing this quantity may occupy 

 50 divisions of the volumeter. 



About 1£ gr. of the salt to be analyzed should be dissolved in 1000 

 times its weight of water — when the decomposition is complete, the 

 smell of the hypochlorite is considered a sufficiently accurate test of 

 excess. The divisions then are to be read oiF and give at once the 

 quantity of chlorine used. Indigo may be used as in ordinary chloro- 

 j metric analysis — but in this case the liquid should be acidulated or the 



indigo may be attacked in preference to the sulphuric acid. If the 

 solutions are neutral, some of the hypochlorite should be added be- 

 fore the acid. 



This mode of analysis is sun-crested as suitable for the lower acids of 

 pnosphorus, arsenic and antimony, &c. Hyposulphite of soda is also 

 proposed as a substitute for arsenious acid in ordinary chlorimetry. 



/« 



G. C. ScH^EFFER. 



Ten pans of logwood are to be exhausted with eighty of boiling water. 

 To the solution one thousandth of its weight of yellow chromate of 

 Potash is to be gradually added — the liquid turns brown and at last blue 

 black— no gum is needed, and the ink is not removed by soaking in 

 water. G. C. S. 



8. On the Application of Liquid Hydrocarbons to Illumination ; by 

 C B. Mansfield, (Chem. Gaz., May, 1849.)— The fluid called by the 

 author benzole, obtained from coal, tar, or any other volatile hydrocar- 

 bon, may be used for this purpose. Through this liquid is to be conduct- 

 ed common air or steam passed over coke, when the air or gas so treated 

 becomes fitted for burning, and gives out a clear white light. Some 

 precautions are to be taken to prevent the evaporation of the fluid, from 

 lowering its temperature below that of the air, which ordinarily ts the 

 Proper temperature for the fluid. When common air is used, the holes 

 must be larger than in <ms jets. The advantages of this mode of illu- 

 mination are simplicity of apparatus, perfect cleanliness and safety, and 

 great brilliancy of the light. Several years since an apparatus on the 

 s ame principle was exhibited in this country— spirits of turpentine were 



