greater (juantitv of bromine, and ether a -\i\\ greater amount. Hut 

 after a certain time products of the action of the bromine on these 

 organic substances are formed in the solutions. Aqueous .solutions of 

 the bromides also absorb a large amount of bromine. 



With respect to iml/nc, it is almost exclusively extracted from the 

 mother liquors after the crystallisation of natural .sodium nitrate (Chili 

 saltpetre) and the ashes of the sea-weed cas ! upon the shores of I'Yance. 

 ( i real r>ritain. and Spain, sometimes in considerable quantities, bv the 

 hi^'h tides. The majority of these sea-weeds are of ihe genera /'/'''/'x, 

 Luini iittrin, ivc. The fused ashes of these sea-weeds are called 'kelp' 

 in Scotland and ' varee ' in Normandy. A somewhat considerable 

 quantity of iodine is contained in these sea-weeds. After being burnt 

 (or subjected to dry distillation ) an a>h is left which chief! v contains 

 salts of potassium, >odium. and calcium. 'Ihe metals occur in the sea- 

 weed as salts of organic acids. ( Mi beinu' burnt ihe.se organic salts are 

 deeompo>ed formin" 1 carbonates of potassium and sodium. llence, 



1 <3 A 



sodium carbonate is found in the ash of sea plants. The ash is dissolved 

 in hot water, and on evaporation sodium carbonate and other salts 

 separate, but a portion of the substances remains in solution. These 

 mother liqm >rs left after the separation of the sodium carbonate contain 

 chlorine, bromine, and iodine in combination with metals, the chlorine 

 and iodine bein^ in excess of the bromine. I:)UIMI kilos, of kelp give 

 a'oout I ( if H i kilos, of sodium carbonate and !> kilos, of iodine. 



The liberation of the iodine from the mother liquor is accomplished 

 with comparative ease, because, chlorine disengages iodine from potas- 

 sium iodide and its other combinations with the metals. Not only 

 chlorine, but also sulphuric acid, liberates iodine from sodium iodide. 

 Sulphuric acid, in acting on an iodide, sets hydriodic acid free, but the 

 latter easily decomposes, especially in t he presence of substances capable 

 of evolving oxvgen, such as chromic acid, nitrous acid, and even ferric 

 salts.' 1 ' <>wino; to its sparing solubility in water, the iodine liberated 



r-i . i; . 



diir.-n nt -..!\.-ni 

 ];. i;- . - i :.-.', i 



. N.,t. LI. IIL. 'I'h.- t.-i |" itiin ni 

 >;_> : . , :. iy <,!' r.r..lnj| .( ) IT.) 

 ' In ..jeiienil. iill I M I, H .( ). ii tin- , _-en proceed from a -iili-tancc- from which 



; i , . \\ , ... , ,| .,.,|. I-', ,r t.lii- re, i , in CM) n pi, m |tl- corre-;pi,iidiii;_' u i! li lln- higher i-ta^'t-s of 

 ... 'd.M ;, ' it ion t'rei|iieni K ;_ is . ,i ISM r ta;_ r e \s hen treated u ilh hydriodir acid. 



. i , i i . .1 hi-i id.-. ,i nd i.-i-i i o> i,l.-. !'.< ). :i Inu.-r ,,xide : the fonm-r 



I-',. A III,, liter s 1 l-',-X .. and Ihi- |o - -a-.- from tlic II,-H,T to ilie 



. /, ,, i , .. ; -, . j '. . . i , , .driodii- acid. < ompi muds of copper 



,.- ,],.. ( ,,M , . ( ,,.\ . , ' ;:,) . . . . oi !ii, 1 1 id.- Ciiv' ). <.r TuX. I-! ven sulphuric; acid, 



