ON  THE  PREPARATION  OF  DAMMARA  VARNISH.  317 
pale  reddish-yellow,  boiled  and  mixed,  after  cooling,  -with  nitric 
acid,  we  obtain  the 
Basic  Salt,  8Fe2  O3,  2N05,  3HO,  in  the  form  of  an  ochre- 
yellow  precipitate,  which  is  difficult  of  solution  in  cold  dilute 
acid,  but  dissolves  readily  in  water,  forming  a  deep  red  fluid. 
The  salt,  washed  with  water,  containing  nitric  acid,  furnished 
on  analysis — 
Fes  O3      .       .    81.92       8  =  640  82-58 
NO5  .       .       .    1447      2      108  13.93 
HO   .      .       .     3-61      3        27  349 
Basic  Salt,  36Fe2  O3,  N05-f  48HO.— When  the  concentrated 
solution  of  nitrate  of  iron,  containing  a  little  excess  of  acid,  is 
boiled  for  a  considerable  time,  a  precipitate  resembling  the  pre- 
ceding is  formed  ;  its  analysis  gave — 
Fe2  O3  .  .  %  .  8544  36  =  2880 
NO5      ...  1.61        1  54 
HO       ...  12-95      48  432 
Basic  Salt,  8Fe2  O3  N05+12HO,  was  obtained  by  treating  an 
excess  of  iron  with  nitric  acid ;  it  forms  a  rust-colored  precipi- 
tate, which  is  difficult  of  solution  in  nitric  acid,  but  dissolves 
more  readily  in  water.    Its  analysis  gave— 
Fe203  .  .  80.33  8  =  640  79-81 
NO5  .  .  .  649  1  54  6-73 
II     .  1348      12       108  13.46 
London  Ohem.  Qaz.,  June  1,  from  Ann.  der  Chem.  und  Pharm. 
ON  THE  PREPARATION  OF  DAMMARA  VARNISH. 
By  W.  Munsel. 
If  dammara  resin  be  dissolved  in  cold  oil  of  turpentine,  a 
milk-white  turbid  varnish  is  obtained ;  this-  turbidity,  however, 
does  not  depend  upon  the  incomplete  solution  of  the  resin,  but 
rather  upon  the  moisture  adherent  to  it.  This  moisture,  as  well 
as  the  water  enclosed  in  the  interior  of  the  resin,  especially  in 
the  white  opake  pieces,  produces  many  defects  in  the  varnish,  as 
when  it  is  prepared  cold  this  water  remains  in  it  in  a  finely-di- 
vided state.  When  such  a  varnish  as  this  is  laid  on,  the  water 
contained  in  it,  although  in  such  small  quantity,  can  neither 
evaporate  nor  soak  into  the  varnished  object;  and  thus  these 
