ON  THE  ALUM  SPRINGS  OF  VIRGINIA. 
265 
became  cloudy,  and  evidence  of  the  separation  of  oil  was  soon 
manifested. 
Under  these  circumstances  the  oil  rises  to  the  surface,  and  is 
found  there  in  a  flocculent  mass  after  the  mixture  has  stood  for  a 
few  hours,  or  during  a  night ;  and  the  measure  of  the  oils  thus 
separated  afford  a  fair  index  of  the  relative  strength  of  the  essences 
examined. 
In  order  to  get  the  oils  in  a  more  definite  state,  the  mixture  in 
which  the  separation  had  been  effected  was  twice  washed  with  an 
equal  volume  of  ether,  and  the  latter,  after  being  decanted,  was 
allowed  to  evaporate  spontaneously.  The  sides  of  the  evaporating 
dish  were  coated  with  a  concrete  oil  of  a  light  orange  color,  and 
at  the  bottom  of  the  dish  was  a  small  quantity  of  fluid,  which,  on 
being  dried  over  sulphuric  acid,  afforded  crystals  of  chloride  of 
calcium.  By  washing  the  contents  of  the  dish  with  ether,  which  had 
been  previously  dried  with  chloride  of  calcium,  and  again  evapo- 
rating the  solution  spontaneously,  the  essential  oil  was  obtained 
free.  It  is  a  concrete  oil,  having  a  powerful  and  characteristic 
odor,  and  of  a  pale  color.  On  the  addition  of  oil  of  vitriol,  it  ac- 
quires a  deep  blood  red  color  and  a  pungent  odor. 
The  mother  liquor,  containing  the  chloride  of  calcium,  from 
which  the  oil  had  been  separated,  on  being  afterwards  evaporated 
afforded  a  very  faint  smell. 
Two  samples  of  essence  examined  in  the  manner  described,  gave, 
in  round  numbers,  one  grain  and  three  grains  respectively  of  es- 
sential oil  from  half-an-ounce  of  the  essence. —  Pharm.  Journ., 
Feb.,  1853. 
Manchester,  Jan.  1  lf/i,  1853, 
ON  THE  ALUM  SPRINGS  OF  VIRGINIA. 
By  Dr.  Thomas  Pollard,  of  Richmond. 
[We  extract  the  following  from  an  article  in  the  Richmond, 
Virginia,  Stethoscope  for  March,  by  Dr.  Pollard,  on  the  Alum 
Springs  of  Rockbridge  and  Bath  counties  of  that  State.] 
The  Rockbridge  Mum  Springs  are  situated  17  miles  west  of 
Lexington,  and  have  rapidly  grown  in  reputation  and  public  favor. 
The  springs  issue  from  the  base  of  a  hill  100  feet  in  elevation, 
and  are  five  in  number.  They  flow  from  the  rock  and  are  sup- 
plied by  the  percolation  of  the  rain  water  through  strata  of  clay 
slate,  which  is  the  source  of  their  mineral  constituents.  The  springs 
