872 
CONVERSION  OF  SALT  MEAT  INTO  FRESH,  ETC. 
used  the  water  of  this  hydrant  had  ever  experienced  the  slightest 
accident.  Nevertheless,  my  experiments  lead  me  to  the  following 
conclusion  :  That  under  certain  circumstances — as,  for  instance, 
the  washing  of  butter, — water  from  copper  hydrants  may  become 
deleterious,  unless  the  pipes  be  tinned  inside. 
It  has  long  been  known  that  the  acids  contained  in  greasy 
substances  will  act  promptly  on  copper ;  but  the  above  experi- 
ment has  demonstrated  to  me,  that  butter  is  perhaps  the  most 
sensitive  reagent  to  detect  the  presence  of  that  metal,  or  of  its 
salts,  in  a  liquid  ;  and  that,  if  iron  has  the  property  of  reducing 
the  salts  of  copper  contained  in  a  very  diluted  solution,  butter 
itself  possesses  the  property  of  forming  a  copper  salt — perhaps 
a  butyrate — which  reveals  the  presence  of  that  metal,  even  when 
the  active  reagents  most  in  use  have  failed  to  give  traces  of  its 
existence. 
I  leave  to  the  masters  of  the  science  the  care  of  completing 
these  experiments,  which  are  certainly  not  devoid  of  interest  in 
a  toxicological  point  of  view. 
Translated  for  the  Philada.  Journal  of  Tbarmacy.  from  L'Union  Tharmaceutique,  Paris. 
CONVERSION  OF  SALT  M  EAT  INTO  FRESH ;  A  FURTHER 
APPLICATION  OF  DIALYSIS. 
By  A.  A.  Whitelaw. 
As  an  appendix  to  the  notice  of  my  process  for  the  utili- 
sation of  brine  [reprinted  in  this  Journal,  pa^e  354,]  I 
now  beg  to  direct  attention  to  a  modification  of  that  process, 
applicable  to  ships  at  see,  by  which  the  qualify  of  the  meat  sup- 
plied to  the  men  may  be  much  improved,  and  their  food  varied. 
The  salt  meat  is  placed  in  a  dialytic  bag  made  of  un tanned 
skin,  or  other  suitable  material,  and  the  bag  rilled  nearly,  but 
not  quite,  full  of  brine  from  the  beef  barrel.  The  d ia ly.se r  is 
then  placed  in  sea  water,  and  the  process  allowed  to  go  on  for 
several  days,  till  the  meat  and  brine  are  sufficiently  freJi  f^r 
use,  or  till  the  brine  in  the  dialytic  bag  is  within  1°  or  2"  of 
Twaddel's  hydrometer  of  the  same  strength  of  sea  water.  In 
this  way,  as  the  brine  becomes  free  from  salt,  the  beef,  which, 
by  the  action  of  salt,  has  been  contracted,  gives  its  salt  to  the 
