400 Foreign and Miscellaneous Intelligence. 



6. PREPARATION OF IODIC ACID. 



The following is a method of preparing this acid, devised and 

 recommended by A. Council, A.M. : The vessel employed was 

 a rather large and tall flask, into which fifty grains of iodine and 

 an ounce of fuming nitric acid were put ; the acid was made to boil, 

 and as soon as any iodine sublimed and condensed on the sides of 

 the vessel, it was washed back again into the liquid by agitation. 

 After the process had been continued some time, a precipitation of 

 white crystalline grains was observed to take place, and the opera- 

 tion of boiling and washing back the sublimed iodine was continued 

 until the free iodine had, to a great extent, disappeared. The 

 whole was then decanted into a shallow basin, and evaporated to 

 dryness. 



Any free iodine which had remained was soon dissipated by the 

 heat. The residue of the evaporation consisted of whitish crystalline 

 grains, which were iodic acid, retaining a little nitric acid, from 

 which they appeared to be freed by one or two solutions in water 

 and re-evaporations, when they lost most of their crystalline appear- 

 ance, and became a whitish deliquescent mass, occasionally with a 

 light purplish tint, from a tendency to decomposition by the heat of 

 evaporation. Where no particular precautions were taken to prevent 

 loss in the state of vapour, and where the process was not continued 

 until the entire disappearance of iodine, the quantity of acid ob- 

 tained approached that of the iodine employed ; a larger proportion 

 of iodine might probably be used with the same quantity of acid *. 



7. METHOD OF MARKING LINEN. 



The necessity of marking the linen of hospitals, &c., in a perfect 

 and durable manner, so as to resist the action of alkalies, soap, &c., 

 is so important as to have induced M. Henry to examine the methods 

 in use, and endeavour to replace them by a better. The sulphate 

 and muriate of manganese, the sulphate and acetate of iron, nitrate 

 of silver, acetate of alumine and iron, and acetate of lead, mixed with 

 gum or indigo, or ink, have been used for the purpose ; but all either 

 require previous or subsequent operations of some nicety, as immer- 

 sion in carbonated alkalies or hydro-sulphurets, or else such degree 

 of care as to be inexpedient in the hands of the women or persons 

 to whom the duty generally devolves. 



The following is the process which M. Henry ultimately recom- 

 mends as the very best. Take one part, by weight, of iron filings, 

 and three parts of vinegar, or acetic acid of s. g. 1056. Mix the 

 filings with half the vinegar, and agitate it continually. As it 

 thickens, add the rest of the vinegar, and also one part of water. 

 Then apply heat to assist the action, and when all the iron is dis- 

 solved, add three parts of sulphate of iron, and one part of gum 

 arabic, previously dissolved in four parts of water. These are to be 



* Jameson's Jour., 1831. p. 72. 



