^m™:Im™'}    Action  of  Oil  of  Turpentine,  etc.  129 
gent  effect  of  the  glycerin  preparation  of  tannin,  dilution  with  water 
is  necessary. 
I  have  not  had  time  to  pursue  this  subject  further,  or  to  examine 
into  the  effect,  noted  by  some  observers,  that  glycerin  prevents  the 
precipitation  of  some  of  the  salts  of  iron  by  alkalies. 
Speculating  on  this  subject,  and  bringing  to  our  aid  those  facts  re- 
lating to  the  properties  and  affinities  of  glycerin  which  are  already 
known  we  find  that  this  substance  is  by  no  means  chemically  inert, 
not  indeed  sufficiently  so  as  to  admit  of  a  general  application  as  a 
solvent.  The  range  of  glycerin  compounds  is  not  at  all  a  limited  one,, 
but  quite  extensive,  comprising  salts  many  of  which  are  well  defined, 
and  which  possess  strong  individual  characteristics  and  properties. 
Of  those  are  the  simple  compounds  of  glycerin  and  the  inorganic 
and  organic  acids,  or  the  more  characteristic  glycerides  or  glyceryl 
ethers.  I  would  hazard  the  suggestion  that  when  glycerin  and  tan- 
nic acid  are  left  in  contact  for  a  considerable  time,  or  when  heat  is 
applied  in  the  pharmacopoeial  process,  that  glycero-tannic  acid,  or 
ether  is  formed.  The  distinguishing  termination  in  applied  to  ethers 
of  this  kind  would  not,  in  this  case,  be  appropriate. 
I  hope  to  resume  this  subject  when  sufficient  leisure  for  further 
experiment  presents  itself. 
Toronto,  Jan.  10,  1874. — Can.  Pharm.  Journ.  Feb.  1874. 
ACTION  OF  OIL  OF  TURPENTINE  UPON  LEAD  AND  TIN. 
By  J.  M.  Merrick.  B.  Sc. 
I  was  recently  consulted  by  a  manufacturer  of  paints  as  to  what 
metal  he  could  use  for  lining  a  large  tank  in  which  he  intended  to 
keep  a  stock  of  oil  of  turpentine.    I  advised  the  use  of  sheet  lead,. 
but  he  met  that  advice  by  producing  a  well  corroded  sheet  of  lead 
with  which  a  turpentine  tank  had  been  lined,  and  a  sample  of  a  white 
powder  which  he  asked  me  to  examine.    I  found  the  powder  to  be  an 
oxycarbonate  of  lead,  and  the  paint  maker  said  that  after  the  tank 
had  been  used  about  forty  days  for  storing  turpentine,  observing  the 
lead  to  be  corroded,  he  had  the  oil  drawn  off,  and  found  a  wheelbarrow 
load  of  this  oxycarbonate  of  lead  upon  the  bottom  of  the  tank.  The 
sample  of  oil  of  turpentine  he  exhibited  was  not  perceptibly  acid,  but 
appeared  to  be  in  a  normal  condition. 
Laurent  (quoted  in  Gmelin's  Handbook,  xiv.  245)  found  white, 
9 
