270     Analysis  of  Commercial  Samples  of  Iodine.  {^uS&wS?** 
this  disinfectant  and  purifier  may  be  gathered  from  the  following, 
figures : 
Chloride  of  lime.  Disinfectant.  100*0  per  ct.  organic  matter 
Quicklime.  "  84-6     "  " 
Alum.  "  80-4     "  " 
Green  vitriol.  "  76*7     "  u 
Chloralum.  «  74-0     "  " 
Chloride  of  magnesium.  "  57*4     "  " 
Thus  the  disinfecting  and  purifying  powers  of  chloralum  stand  be- 
low those  of  alum,  or  sulphate  of  alumina  and  copperas  (protosul- 
phate  of  iron),  which  further  recommend  themselves  by  their  much 
greater  cheapness. 
To  sum  up  the  argument,  concerning  the  value  and  composition  of 
the  preparation  of  chloralum  :  1.  The  preparations  of  chloralum  have 
nothing  in  common  with  the  similarly  sounding  chloral  hydrate,  and 
are,  in  point  of  fact,  mixtures  of  chloride  of  aluminium.  2.  The  pre- 
parations of  chloralum  contain  chlorine  combinations  of  lead,  copper 
and  arsenic,  which  renders  their  employment  not  free  from  danger, 
and  which  would  render  their  employment  as  a  medicine  or  as  an 
astringent  for  open  or  suppurating  wounds  dangerous.  3.  The  price 
of  the  preparations  of  chloralum  bears  no  relation  either  to  their 
nature  or  their  effect.  Considering  that  the  liquid  chloralum  yields 
a  clear  profit  of  at  least  700  per  cent.,  and  the  wadding  400  per  cent., 
the  limits  of  honest  trading  may  be  considered  as  overstepped.  4. 
The  result  of  these  experiments  is  that  chloralum  and  the  prepara- 
tions made  from  the  same  must  be  classed  amongst  the  worthless 
arcana,  and  in  the  interest  of  the  public  health,  as  well  as  in  the  ma- 
terial interests  of  the  public,  a  most  decided  warning  must  be  given 
against  the  purchase  of  the  same. — Chemical  Review,  Lond.,  March, 
1872,  from  Industrie  Zeitung. 
ANALYSIS  OF  COMMERCIAL  SAMPLES  OF  IODINE. 
By  Prof.  J.  A.  Wanklyn. 
Owing  to  the  high  price  of  iodine  and  its  numerons  applications  in 
the  chemical  arts,  its  analysis  is  very  important,  and  at  the  same  time 
frequently  very  difficult. 
The  process  is  to  dissolve  a  known  weight  of  the  sample  in  a  solu- 
tion of  sulphurous  acid,  and  to  precipitate  the  iodine  by  means  of  a 
