448 
GLEANINGS  FROM  THE  GERMAN  JOURNALS. 
Preparation  of  Lactic  Acid. — Lautemann  alters  Bensch's  pro- 
cess (see  Gmelin's  Handbook,  Cavendish  edition,  xi.  475,)  by 
using  sugar,  tartaric  acid,  milk  and  cheese,  as  directed  by  B., 
J  more  of  water,  and  instead  of  chalk,  ordinary  white  zinc  ;  the 
temperature  ought  to  be  kept  at  from  40  to  45°  C.  (104  to  113°F.) 
and  the  mixture  frequently  agitated  ;  lactate  of  zinc  crystallizes 
in  from  8  to  10  days.  The  whole  is  heated  to  boiling,  filtered, 
evaporated,  again  filtered  and  after  crystallization,  recrystallized; 
the  lactate  is  then  dissolved  in  boiling  water  and  decomposed  by 
sulphuretted  hydrogen  ;  the  acid  liquor  is  evaporated,  and  freed 
from  mannite  by  dissolving  in  ether  and  distilling  it  off.— (Vol. 
cxiii.  242,  243.) 
Decomposition  of  Carbonic  Acid  by  red  hot  Copper. — Laute- 
mann confirms  Perrot's  observation  that  pure  metallic  copper 
does  not  decompose  carbonic  acid,  which  is  reduced  to  carbonic 
oxide  by  the  presence  of  some  iron  or  zinc. — (Vol.  cxiii.  238, 
239.) 
Volatility  of  Phosphoric  Acid. — Anhydrous  phosphoric  acid 
volatilizes,  according  to  Lautemann,  when  heated  in  a  test  tube 
over  an  ordinary  spirit  lamp,  with  the  exception  of  a  small 
portion  which  combined  with  the  constituents  of  the  glass. — 
(Vol.  cxiii.  240.) 
Electrolytic  Observations. — Prof.  H.  Kolbe  found  that  succi- 
nate of  soda  yields,  on  the  positive  pole^carbonic  acid  and  oxide 
of  methyle ;  lactate  of  potassa,  however,  carbonic  acid  and 
aldehyde. — (Vol.  cxiii.  244.) 
On  Copal  Resin. — Before  copal  is  used  for  the  preparation 
of  varnishes,  it  is  subjected  to  a  partial  dry  distillation  ;  Manilla 
copal  yields  a  dark  brown  ;  African  copal  a  greenish  distillate, 
containing  copper  from  the  retort.  This  distillate  contains  an 
acid,  copalic  acid,  which  has  not  been  obtained  in  a  pure  state, 
several  oils  and  a  tarlike  body.  Prof.  J.  J.  Schivler,  found  the 
oil  rectified  between  160  and  165°  C,  to  be  of  a  pleasant  odor, 
very  disagreeable  taste,  and  the  composition  C20HI6 ;  the  oil 
boiling  above  215°  contained  15»6  per  cent,  oxygen  and  proba- 
