PARCHMENT- PAPER. 
423 
burning  with  a  weak  flame  and  the  production  of  a  violet  colored 
smoke.  Further  investigation  into  its  nature  has  meanwhile  been 
prevented  by  falling  short  of  material — London  Phar.  Jour. 
June  1,  1857. 
PARCHMENT-PAPER. 
At  a  meeting  of  the  Royal  Institution,  held  on  Friday,  the 
3rd  of  April,  the  subject  of  the  discourse  delivered  by  the  Rev. 
J.  Barlow,  Vice-President  and  Secretary  to  the  Institution,  was 
"  On  some  modifications  of  woody  fibre  and  their  applications,"  in 
the  course  of  which  an  interesting  description  was  given  of  the 
substance  to  which  the  name  Parchment-paper  has  been  applied. 
This  substance  is  the  invention  of  Mr.  W.  E.  Gaine,  C.  E.,  by 
whom  the  process  for  its  preparation  has  been  patented.  Mr. 
Barlow  having  described  several  of  the  applications  of  woody 
fibre,  and  particularly  its  application  in  the  manufacture  of  paper, 
referred  to  the  chemical  and  physical  changes  effected  in  paper 
and  analogous  fabrics  by  treating  them  with  chemical  agents. 
He  contrasted  with  the  pyroxylised  textures  of  Kuhlmann  and 
the  gun-paper  of  Pelouze,  the  woven  fabrics  subjected  to  Mercer's 
process,  and  the  Parchment-paper,  the  invention  of  Mr.  Gaine. 
By  acting  on  cloth  with  chloride  of  zinc,  tin,  or  calcium,  with 
sulphuric  and  arsenic  acid,  and,  especially,  by  the  caustic  alkalies 
in  the  cold  (the  temperature  sometimes  being  lowered  to  — 10° 
Fahr.),  Mr.  Mercer  has  obtained  many  important  effects  on  the 
fineness  and  general  appearance  of  cloth,  and  its  susceptibility  of 
dye.  This  subject  was  brought  before  the  Royal  Institution  by 
Dr.  Lyon  Playfair,  C.B.,*  and  it  has  since  been  closely  investi- 
gated by  Dr.  Gladstone-!  Mr.  Mercer  also  experimented  on  the 
effect  of  acids  on  paper.  It  being  known  that  sulphuric  acid, 
under  certain  conditions,  modified  vegetable  fibre,  Mr.  Gaine 
instituted  a  course  of  experiments  to  ascertain  the  exact  strength 
of  acid  which  would  produce  that  effect  on  paper  which  he  sought, 
as  well  as  the  time  during  which  the  paper  should  be  subjected 
to  its  action.    He  succeeded  in  discovering,  that  when  paper  is 
*  Proceedings  of  the  Royal  Institution,  vol.  i.,p.  134  (1852.) 
■j-  Journal  of  the  Chemical  Society,  vol.  v.,  p.  17  (1853.) 
