The  gas  will  rise  and  displace  the  water,  which  will  flow  out
at  d.  When  full,  put  the  cap  on.  To  get  the  gas  out  of  the
gasometer,  attach  a  rubber  tube  to  e,  pour  water  into  the
upper  part  of  the  gasometer,  open  the  stop-cock  a  and  that
at  e,  when  the  gas  will  flow  out,  and  the  current  can  be  regu-
lated by  means  of  the  stop-cock  at  e.
The  arrangement  of  the  retort  is  shown  in  Fig.  23.
FIG.  23.  FIG.  24.
PHYSICAL  PROPERTIES  OF  OXYGEN.
Experiment  19. — Inhale  a  little  of  the  gas  from  one  of  the
bottles.     Has  it  any  taste  ?  any  odor  ?  any  color  ?


CHEMICAL  PROPERTIES  OF  OXYGEN.
Experiment  2O. — Turn  three  of  the  bottles  containing  oxy-
gen with  the  mouth  upward,  leaving  them  covered  with  glass
plates.  Into  one  introduce  some  sulphur  in  a  so-called  de-
flagrating-spoon,  which  is  a  small  cup  of  iron  or  brass  at-
tached to  a  stout  wire  which  passes  through  a  metal  plate,
usually  of  tin  (see  Fig.  24).  In  another  put  a  little  char-


742       EXPERIMENTS  TO  ACCOMPANY  CHAPTER  II.
coal  (carbon),  and  in  a  third  a  piece  of  phosphorus*  about
the  size  of  a  pea.  Let  them  stand  quietly,  and  notice  what
changes,  if  any,  take  place.  Sulphur,  carbon,  and  phos-
phorus are  elements,  and  oxygen  is  an  element.  It  will  be
noticed  that  the  sulphur  and  the  carbon  remain  unchanged,
while  some  change  is  taking  place  in  the  vessel  containing  the
phosphorus,  as  is  shown  by  the  appearance  of  white  fumes.
