IODIDE OF POTASSIUM. 115 



liquid is to be diluted with 32 pts. water, and will last for 

 months. 



Bromo and lodohydric Acids. — Mene (Comptes Rendus, 

 1849) gives the following economical, easy, and safe process 

 for making the bromohydric and iodohjdric acids, which we 

 take from Silliman, ix. 421. 



6 pts. crystallized sulphite of soda are to be moistened with 

 1 pt. water, and 3 pts. bromine or iodine then added, and heat 

 applied. The gases pass over pure, provided the neck of the 

 retort be loosely plugged with asbestos, to intercept bromine 

 or iodine vapors. The sulphite aids the bromine or iodine 

 in the decomposition of the water, the latter taking the hy- 

 drogen, the sulphurous acid the oxygen. 



Iodide of Potassium. — Criquelion's method (Journ. de Chem. 

 Med. iv.) is to mix together, thoroughly, 40 pts. calcined 

 lime slaked in water, and 14 pts. iron filings. To this mixture 

 add, during constant stirring, and portionwise, 94 pts. iodine. 

 When the liquid produces only an ochrey stain upon startled 

 paper, it is to be filtered and washed, and the filtrate pre- 

 cipitated by carbonate of potassa. Filter, wash, and evaporate 

 to crystallization. 



According to Wackenroder, a small amount of sulphide 

 may be found in iodide of potassium by the evolution of sul- 

 phohydrogen with protochloride of tin. 



Iodide of Lead. — Huraut's experiments (Journ. de Pharm. 

 1849) upon the comparative advantages of the several methods 

 of preparing iodide of lead, prove that the nitrate of lead 

 and iodide of calcium afi"ord the best results, both as to quality 

 and quantity. 



On the Nitrites. — Fischer, in a paper upon the nitrites 

 (Pogg. Ann. Ixxiv.), gives processes for the preparation of 

 several. The potassa nitrite is made by heating the nitrate 

 to redness, separating the nitrate by recrystallization, and the 

 free potassa by acetic acid and alcohol. 



3Iagnesian Lemonade. — Massignon prepares citrate of 

 magnesia lemonade (Journ. de Pharm. xii.) by making 5 grm. 

 carbonate of magnesia into a milk with water, pouring it into a 



