Chemical Scienei^. 479 



weakei-. It is slowly dissipated in the air, is very soluble in water 

 and alcohol, producing amber-coloured solutions. If brought, irt 

 the solid state, into contact with a dry, combustible substance, it is 

 decomposed, iodine being evolved. Phosphorus and potassium 

 are inflamed by it. It changes the blue litmus infusion to green. 

 If an alkali be poured into its solution, the latter is instantly ren- 

 dered colourless ; whereas if alkali be added to solution of iodous 

 acid, iodine is precipitated. The discoloration is due to the com- 

 bination of the alkali with the iodine which is taken from the com- 

 pound, — a further proof of the weakness of the affinity between 

 oxygen and iodine. 



If the addition of oxygen be continued after the formation of 

 the oxide of iodine, then iodous acid is formed ; and, if the lamp 

 applied to the bottom of the retort be at the same time removed to 

 the neck, the formation of the iodous acid will be much facilitated. 



Finally, oxide of iodine is always formed when iodine is heated 

 in close vessels containing air, and air may be used in place of oxy- 

 gen in the process above described. If iodine be put into a retort^ 

 and then a second be sealed hermetically to the first, a small ca- 

 pillary hole being left in the neck ; the iodine being heated suc- 

 cessively, first in one part and then in another of the apparatus, 

 wherever it assumes the solid form, will gradually change into 

 oxide of iodine. — Giomale deFisictty ix. p. 387. 



^.Quantity of Charcoal obtained from Wood. — The following 

 table contains the results obtained by M. Karsten from one hun- 

 dred parts of the shavings of woods which had been carefully dried 

 in the air. Two modes of carbonization were used ; the one rapid 

 and commencing with a high temperature, the other slow and gra- 

 dual. The quantity of ashes wds obtained by incineration of the 

 charcoal under a muffle. 



