Intelligence and Miscellaneous Articles. 421 



parts of osmiuret of iridium require ten parts each of chlorate and 

 hydrate of potash, and the operation may be conveniently performed 

 over a lamp in a porcelain crucible ; it requires about half an hour. — 

 Journ. de Pharm. et de Ch.„ Septembre 1846. ,,m; i 







ANHYDROUS ALCOHOL. 



A I. Casoria proposes to employ perfectly dry sulphate of copper 

 to render alcohol anhydrous, and also to employ it as a test for as- 

 certaining that it is perfectly free from water. For these purposes 

 he saturates alcohol, of 83° by the instrument of Gay-Lussac, with 

 fused chloride of calcium : he distilled one-third of the liquid, and 

 to about 7500 grains he added a small quantity of the anhydrous sul- 

 phate, and kept the mixture in a well-closed bottle which was shaken 

 occasionally. The salt, by combining with the water of the alcohol, 

 resumes its blue colour, and fresh portions of the salt are to be added 

 till the blue colour ceases to be produced : the alcohol after distilla- 

 tion may then be considered anhydrous. 



To determine the absence of water from alcohol, a small quantity 

 of dry sulphate of copper is to be put into a glass tube and the alco- 

 hol poured upon it : if no colour be generated the alcohol may be 

 regarded as anhydrous. In performing this experiment it is requi- 

 site to keep the tube closed, as the moisture of the atmosphere 

 would interfere with the accuracy of the result. — Journ. de Chim. 

 Med., Juillet 1846. ..-moloo dsjmolisrr obsq a vino ano 

 laono'i sdt avis ,9mil *to olsh^ — " 



ACTION OF FERROCYANIDE OF POTASSIUM ON THE TARTRATE 

 , -fa r AND CITRATE OF IRON, ETC. I iejsL 



M. Calloud remarks, that on examining the action of ferrocyanide 

 of potassium on the tartrate and citrate of iron, some remarkable 

 reactions occur, which are not common to all the salts of iron . 



The neutral tartrate of iron, like the neutral citrate, is precipitated 

 by the alkaline ferrocyanides, like all the other persalts of iron; but 

 the precipitate formed does not possess all the appearances of com- 

 mon prussian blue ; its colour is often much modified, without its 

 being occasioned by an excess of either of the salts employed. Tar- 

 trate of iron with excess of tartaric acid, on the contrary, does not 

 precipitate the solution of ferrocyanide of potassium ^'but the liquor 

 becomes immediately blue and remains clear. After a considerable 

 time has elapsed a slight precipitate is formed, which is hot dense, 

 like prussian blue ; the liquor remains nevertheless bright and blue. 



The properties of the blue liquor, obtained by evaporating to dry- 

 ness the mixture of tartrate of iron with excess of acid with ferro- 

 cyanide, are not altered by evaporation to dryness. It is concen- 

 trated by heat without being decomposed : the product of the eva- 

 poration remains of a fine deep blue colour, and redissolves in water ; 

 ammonia however destroys its colour ; this effect is explained by the 

 immediate formation of the double tartrate of iron and ammonia, 

 which, like the other double tartrates of iron and alkalies, does not 

 act upon the ferrocyanide of potassium. 



Citrate of peroxide of iron with excess of citric acid and ferro- 



