ARTESIAN  WATER  OF  CHARLESTON,  S.  C. 
333 
flask,  and  in  so  doing  to  use  a  cork  which  was  exposed  to  the 
action  of  the  fumes  from  boiling  nitric  acid  for  several  hours,  I 
found  the  best  preservative  to  consist  of  a  coating  of  silicate  of 
soda  and  powdered  glass.  The  cork  having  been  bored  to  suit 
the  size  of  the  tube,  was  soaked  for  two  or  three  hours  in  a  so- 
lution of  silicate  of  soda,  consisting  of  one  part  of  commercial 
concentrated  solution,  to  three  parts  of  water.  The  tube  was 
next  inserted,  and  when  dry,  the  cork  was  covered  with  a  paste 
made  by  mixing  the  condensed  solution  of  the  silicate  with  pow- 
dered glass  in  such  proportion  as  to  form  a  mass  of  about  the 
same  consistence  as  that  of  putty.  This  is  spread  on  the  under 
surface,  and  then  washed  with  a  solution  of  chloride  of  calcium. 
It  soon  hardens,  so  I  think  it  advisable  to  make  the  connection 
with  the  flask  whilst  the  paste  is  in  a  plastic  state,  and  to  allow 
it  to  become  solid  before  applying  heat  to  the  vessel  containing 
the  acid. 
Corks  protected  in  this  manner  were  but  slightly  acted  upon, 
though  remaining  over  the  boiling  nitric  acid  more  than  four 
hours,  and  over  hot  acid  for  ten.  In  some  instances,  when  not 
entirely  covered,  the  vapor  softened  the  cork  beneath  the  silicate 
to  the  depth  of  about  a  quarter  of  an  inch,  but  the  cement  proved 
sufiiciently  strong  to  form  a  compact  diaphragm,  enabling  the 
tube  to  be  removed  from  the  flask  without  danger  of  the  fluid 
contained  being  contaminated.  I  would  suggest  also  the  appli- 
cation of  this  cement  as  a  luting  for  chemical  apparatus  for  gen- 
eral use,  as  I  find  that  it  remains  unaff'ected  even  when  im- 
mersed in  strong  nitric,  sulphur,  or  muriatic  acids.  The  im- 
mersion in  these  liquids  was  .made  whilst  the  plaster  was  still 
soft,  with  the  only  perceptible  efi'ect  of  hardening  the  same  im- 
mediately.   Yours,  &c.,  Rob't.  F.  Fairthorne. 
Philadelphia,  March  22d,  1869. 
— Jour,  Franklin  Institute,  April,  1869. 
ARTESIAN  WATER  OF  CHARLESTON,  S.  C. 
By  Prof.  C.  U.  Shepard,  Jr. 
The  analysis  of  the  water  of  the  artesian  well  of  this  city  may 
interest  some  readers,  not  only  the  scientific  who  may  possibly 
