174  VARIETIES. 
phosphorus  upon  aqueous  acetone  gives  the  same  results  as  that 
of  hydriodic  acid  ;  but  the  most  convenient  method  consists  in 
heating  acetone  with  a  concentrated  aqueous  solution  of  hydri- 
odic acid  in  a  matrass. 
As  is  shown  by  the  formula  above  indicated,  4  molecules  of 
ether  are  produced  from  2  molecules  of  acetone.  Taking  as  a 
starting  point  4  molecules  of  acetic  acid,  we  may  regard  the  re- 
action in  question  as  completing  a  decomposition  of  the  acetyle 
radicals  which  they  contain,  which  is  commenced  by  their  con- 
version into  acetone. 
It  is  probable  that  this  reaction  is  general,  and  that  it  will 
allow  us  to  pass  from  any  acid  to  an  inferior  alcohol,  and  conse- 
quently from  one  alcohol  to  any  inferior  alcohol.  It  at  the  same 
time  furnishes  us  with  a  reagent  which  will  allow  us  to  study 
even  the  radicals  of  the  acids  Ibid  from  Oomptes  Bendus, 
June  14,  1858. 
PRACTICAL  OBSERVATIONS  ON  THE  INTRODUCTION  OF  PRE- 
SERVATIVE  SOLUTIONS  INTO  RAILWAY  TIMBER. 
By  F.  Hewson,  C.  E. 
The  use  of  timber  upon  our  railroads  is  considered  indispensable  ;  it  is 
everywhere  found  in  the  superstructure  of  our  tracks,  and  forms  the  chief 
material  of  our  bridges ;  its  renewal  is  the  most  expensive  item  of  repairs. 
The  life  of  a  sill  seldom  extends  longer  than  eight  years,  and  the  rate  of 
annual  depreciation  being  12^  per  cent.,  can  be  applied  to  the  estimate  for 
the  durability  of  the  bridges,  and  those  structures  which  are  unprotected 
against  the  assaults  of  heat  and  moisture,  the  active  and  unfailing  agents 
of  decay. 
There  are  cycles  in  the  history  of  a  railroad  like  that  of  nations  ;  each 
has  its  era  of  good  feeling,  and  the  blessings  of  cheap  government,  to  be 
followed  by  discontent  and  grievous  burthens.  The  close  of  the  first  octen- 
nial period  in  the  existence  of  a  railroad  track,  is  marked  by  the  entire  re- 
newal of  its  wooden  superstructure,  involving  an  additional  expenditure 
for  labor,  About  a  year  or  two  preceding  this  troublesome  epoch,  the 
managers  and  proprietors  become  alarmed  at  the  rapid  and  disproportion- 
ate increase  in  their  repair  accounts ;  the  spirit  of  economy  and  reduction 
