132  Gleanings  from  the  German  Journals.  {A%i°rch,i£tra1, 
substances  (impurities)  may  be  present  in  the  solvents  from  which 
iodoform  is  recrystallized,  thus  contaminating  the  crystals,  or  they 
may  be  present  in  the  solvents ;  such  substances  as  retard  the  change, 
if  present  in  minute  quantity,  are  hydroquinone,  pyrogallic  acid,  ani- 
line, pyridine  bases  and  aldehyde. — Pharm.  Ztg.,  1889,  31. 
Fluorescence. — E.  Geissler  examined  a  yellow  powder  used  for  de- 
stroying the  fluorescence  of  petroleum  oils  in  the  proportion  of  0*2-0*3 
gm.  for  100  cc.  oil ;  it  proved  to  be  nitro-naphthalin.  Nitrobenzol 
also  possesses  this  property  although  not  to  such  a  marked  degree. 
The  interesting  observation  was  made  that  the  fluorescence  of  quinine 
salts  was  destroyed  by  a  little  of  these  chemicals.  If  light  be  made  to 
traverse  solutions  of  these  substances  it  will  not  produce  the  fluores- 
cent effect  either  upon  quinine  solutions  or  petroleum  oils ;  this  is  ex- 
plainable by  the  possible  absorption  of  the  blue  rays  by  nitro-benzol 
and  nitro-naphthalin. — Pharm.  Centralh.,  1889,  11. 
Russian  turpentine  from  Pinus  sylvestris  contains  about  thirty  per 
cent,  of  a  crystalline  acid  C40H58O5  obtainable  by  extracting  the  tur- 
pentine with  50-60  per  cent,  alcohol  and  treating  the  granular  residue 
with  boiling  alcohol,  which  solution  solidifies  to  a  crystalline  mass  on 
cooling.  The  acid  is  insoluble  in  water,  soluble  in  alcohol,  glacial 
acetic  acid,  ether  and  carbon  disulphide ;  it  melts  at  143°,  boils  at 
360°,  and  is  converted  by  HC1  into  a  modification  melting  at  159°- 
160°.— W.  Schkatelow,  Apoth.  Ztg.,  1889,  99. 
Hyponitrous  oxide  or  nitrogen  monoxide  can  be  obtained  perfectly 
pure  by  heating  5  parts  crystallized  stannous  chloride,  10  parts  hy- 
drochloric acid  sp.  gr.  1*21,  0*9  parts  nitric  acid  sp.  gr.  1*38,  until  the 
mixture  boils,  when  a  steady  evolution  takes  place  according  to  the 
reaction : 
2HN03+4  SnCla+8  HC1=4  SnCl4+N20+5  H20. 
The  above  proportions  must  be  strictly  adhered  to. — G.  Campani, 
Chem.  Rpt,  1889,  5. 
Cobalt  and  Nickel. — Kriiss  and  Schmidt  in  redetermining  the 
atomic  weights  of  these  metals  by  precipitating  a  neutral  solution  of 
auric  chloride  by  means  of  metallic  cobalt  and  nickel,  obtained  quite 
variable  results,  due  to  supposed  admixture  of  Co  and  Ni  with  the 
precipitated  gold.  To  control  this  error  the  gold  precipitate  was  dis- 
solved and  reprecipitated  by  addition  of  sulphurous  acid  ;  even  now 
the  results  were  still  discordant.  In  washing  the  gold  precipitate  the 
color  of  the  washings  disappeared  and  then  became  finally  greenish  j 
