182 
VARIETIES. 
At  first  Mr.  Carlevaris  used  magnesia,  and  also  carbonate  of  magnesia. 
But  he  found  afterwards  that  the  chloride  gave  better  results. — Correspon- 
dence of  Prof.  Nickles,  in  Silliman's  Journal. 
Acclimatization  of  the  Ostrich. — In  my  letter  of  April,  1861,  I  have 
spoken  of  the  attempts  to  acclimatize  the  Ostrich.  The  Society  of  Accli- 
matization continues  to  watch  and  encourage  these  efforts.  They  now  be- 
gin to  hope  that  even  in  temperate  climates,  the  Ostrich  may  figure  among 
the  useful  animals.  The  following  are  the  facts  upon  which  these  hopes 
are  founded,  We  have  already  seen  that  these  animals  can  reproduce  in 
captivity,  but  as  yet  only  in  the  warm  regions  of  Europe,  at  Florence,  Mar- 
seilles, Madrid,  or  in  Algiers.  This  year,  however,  a  birth  of  ostriches  has 
taken  place  in  the  cooler  region  of  Grenoble,  in  the  garden  of  acclimatiza- 
tion of  the  Regional  Society  of  the  Alps. 
The  ostriches  at  the  time  of  breeding  were  kept  in  a  chamber.  After 
46  days  two  young  ones  appeared,  to  which  the  female  seemed  as  devoted 
as  she  had  been  indifferent  to  the  eggs.  On  this  occasion,  as  has  been  be- 
fore observed,  the  little  ones  placed  themselves  only  under  the  male,  and 
received  no  nourishment  from  the  parents. 
After  the  results  obtained  in  Spain,  and  since  in  England,  we  may  hope 
also  to  acclimatize  the  Cassowary. —  Correspondence  of  Prof  .  Nickles,  in  Sil- 
liman's  Journal. 
On  the  Hydraulicity  of  Magnesia. — M.  H.  St.  Claire  Deville  read  a 
note  before  the  Academy  of  Sciences,  December  4,  1865,  of  considerable 
industrial  importance.  He  said  that  seven  years  ago  M.  Donny  sent  him 
a  specimen  of  magnesia  prepared  by  the  calcination  of  the  chloride.  Some 
of  this,  which  was  in  compact  anhydrous  lumps,  he  left  for  several  months 
under  a  tap  in  his  laboratory,  constantly  exposed  to  running  water.  In 
this  time  ifc  took  a  remarkable  consistence,  became  hard  enough  to  scratch 
marble,  and  as  translucid  as  alabaster.  After  six  years'  exposure  to  the 
air  it  has  in  nowise  changed,  and  its  analysis  gave  the  following  results: — 
Water   27-7 
Carbonic  acid        .....  8-3 
Alumina  and  oxide  of  iron       .         .         .  1-3 
Magnesia      ......  57-1 
Sand           ......  5.6 
100-0 
Thus  the  substance  appears  to  be  essentially  a  crystallized  hydrate  of  mag- 
nesia, like  brucite,  which  does  not  absorb  carbonic  acid.  To  prove  that  it 
really  was  so,  M.  Deville  prepared  magnesia  by  calcining  the  nitrate, 
powdered  it,  made  it  into  a  semi-plastic  mass,  and  sealed  it  in  a  tube  with 
some  boiled  distilled  water.  After  some  weeks  the  mass  became  as  hard 
and  compact  as  the  other,  and  also  crystalline  and  translucid.    After  dry- 
