20      Action  of  Acids  upon  Zinc  Containing  Lead,    i^"^' j^nl'mn^^"^' 
tremely  deliquescent,  and  in  practice  it  is  always  better  to  allow  them 
to  completely  liquefy  in  the  mortar  before  attempting  to  make  the 
mass.  Out  of  several  excipients  tried,  pulv.  althseae  and  magnesia 
answered  the  best,  the  former  helping  to  bind  the  mass  and  the  latter 
absorbing  the  superfluous  moisture.  The  strength  usually  ordered  is 
2  grains  in  each  pill ;  this  requires  1 J  grain  of  each  of  the  powders. 
Among  the  scale  preparations  ferri  et  quininse  cit.  and  beberinse 
sulph.  are  sometimes  ordered  in  pill ;  syrup  is  the  best  excipient  for 
the  former,  and  glycerin  for  the  latter. 
Inf.  serpentarice,  prepared  strictly  according  to  the  present  Phar- 
macopoeia, is  incompatible  with  tr.  iodi,  with  which  it  is  sometimes 
prescribed.  It  is  ordered  to  be  made  from  the  root  in  No.  20  pow- 
der, and  thus  a  certain  amount  of  starch  is  dissolved  out,  which,  of 
course,  in  this  case,  combines  with  the  free  iodine  to  form  iodide  of 
starch,  giving  a  dark-blue  inky-looking  mixture.  This  contrasts 
strongly  with  a  similar  mixture  made  with  infusion  prepared  from  the 
whole  root,  this  remaining  quite  transparent,  and  containing  free 
iodine,  thus  carrying  out  the  intention  of  the  prescriber,  which  it  is 
the  duty  of  every  dispenser  to  do. 
Specimens  of  the  various  pills  mentioned  in  the  paper,  and  the  two 
infusions  combined  with  iodine,  were  handed  round  for  criticism  and 
comparison. — Phar.  Jour,  and  Trans.,  December  3,  1887,  p.  472.  . 
ACTION  OF  ACIDS  ON  ZINC  CONTAINING  LEAD.^ 
By  W.  Spring  and  E.  Van  Aubel. 
The  authors  have  investigated  the  action  of  hydrochloric,  hydro- 
bromic,  hydriodic,  and  sulphuric  acids  on  zinc  containing  0'6  per  cent, 
of  lead,  prepared  by  melting  zinc  with  litharge.  The  metal  was  cast 
into  cylinders  1 7  mm.  in  diameter,  covered  with  wax  in  such  a  way 
that  only  one  of  the  basal  planes  was  exposed  to  the  action  of  the 
acid.  The  hydrogen  evolved  was  collected  in  the  apparatus  previously 
used  in  investigations  on  the  action  of  acids  on  marble  (Bull.  Soc, 
Chim.j  xlvii,  927),  and  the  volume  of  the  gas  was  read  oflP  at  regular 
intervals. 
^Ann.  Chim.  Phys.  [6],  xi,  505-554.  Reprinted  from  Jour.  Chem.  Soc,  1887^ 
p.  1074. 
