Miscdl/anies. 37:7 



vessel I used was a rather large and tall flask, having a narrow orifice. 

 In one trial I used twenty five grains of iodine, and half an ounce 

 measure oi fuming nitric acid ; and in another, I employed twice 

 these quantities of the materials. After introducing the iodine and 

 acid into the flask, the liquid was made to boil. 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 prcfcess 

 had been continued ^ome time, a precipitation of white crystalline 

 grains was observed to take place 5 and the operation 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 much of their crystalline appearance, and became a whitish 

 deliquescent mass, occasionally with a slight purplish tint, from a ten- 

 dency to decomposition by the heat of evaporation. 



The general properties of the matter thus obtained, sufiiciently 

 identified it with iodic acid. Exposed to a sufficient heat, it was 

 decomposed, and iodine sublimed. Its solution in water gave a pre- 

 cipitate with nitrate of silver, soluble in ammonia. Saturated with 

 potash, it gave by evaporation a salt composed of grouped cubical 

 crystals, and deflagrating on hot charcoal. 



The quantity of the acid obtained by this process, of course, must 

 vary, according to the care taken to prevent the dissipation and loss 

 of iodine. Where no particular precautions were taken to prevent 

 its loss in the state of vapor, and where the process was not con- 

 tinued until the entire disappearance of iodine, the quantity of acid 

 obtained approached that of the iodine employed. In operating with 

 the relative proportions of iodine and acid which I have mentioned, 

 I have no doubt that a farther addition of iodine might be made to 

 the liquid, after the acidification of what had been at first introduced; 

 and the process might then be farther continued, as before. 



I find, conformably to the observation of M. Sernlias, that iodic 

 acid does not attack gold. Its solution seems to have no action on 

 that metal even when aided by heat. It is equally inert in regard t» 

 platinum. Zinc is at first attacked by it with eiFervescence, especial- 

 ly when diluted ; but the action ceases almost immediately, appa- 



VoL. XXL— No. 2. 48 



