Nitrogen  and  Oxygen  and  of  Argon  and  Oxygen.        647 
Table  III. 
Pn2/Po2= 4-655.         0  =  5-48-0-0207  m. 
Temp.  79o,07  Abs.    Pure  oxygen  has  vapour-press.  =  200  mm. 
Molec. 
percent. 
Molecular  percentage 
Nitrogen  in  Vapour ; 
Total  Pressure : 
mm. 
Part. 
Part, 
No. 
N2in 
liquid. 
Pressure 
Nitrogen. 
Pressure 
Oxygen. 
Obs. 
obs. 
calc. 
cliff. 
obs. 
smoothed 
diff. 
% 
mm. 
mm. 
1... 
0 
0 
0 
200 
200 
0 
200 
2... 
3-4 
167 
16-0 
+'•7 
233-2 
231-5 
+"•7 
37-0 
194-5 
3... 
107 
39-2 
38-7 
-f -5 
297-8 
295-5 
+   -8 
114-3 
181-2 
4... 
197 
55-5 
554 
+■1 
371-8 
371-5 
+  "I 
205-8 
165-7 
5... 
27-8 
654 
65-4 
0 
435-7 
435-5 
+  -o 
284-8 
150-7 
6... 
40-5 
75-8 
759 
-•1 
529-7 
530-0 
-  -o 
402-2 
127-8 
7... 
510 
821 
82-1 
0 
(599)* 
604-0 
-   -8 
495-5 
108-5 
8... 
60-4 
86  4 
86-6 
.o 
—  - 
660-4 
667-0 
-1-0 
577  6 
894 
9... 
72-8 
91-5 
91-3 
+  •2 
746  0 
750-0 
-  -5 
684-7 
65-3 
10... 
82-8 
94-8 
94-8 
0 
815-5 
816-0 
-  -o 
773-6 
42-4 
11... 
90-8 
97-6 
97-2 
+  •4 
872-5 
870-0 
+  '3 
845-6 
24-4 
12... 
99-7 
99-7 
99-95 
-•15 
9310 
928-5 
4-  -2 
92S-0 
0-5 
13... 
(100-0) 
(100-0) 
... 
931-0 
931-0 
0 
*  In  the  case  of  Exp.  7,  the  total  pressure  was  by  a  slip 
circulation  and  is  therefore  certainly  too  low. 
only  during 
Discussion  of  Residts. 
I£  the  ratio  of  nitrogen  to  oxygen  in  the  vapour  be  com- 
pared with  the  same  ratio  for  the  liquid,  it  is  found  that  the 
quotient  of  these  two  ratios  is  a  linear  function  of  the  mole- 
cular composition  of  the  liquid.  Thus  taking  the  results  of 
Table  II.  we  find  that  the  experimental  values,  i.e.  those 
values  given  in  the  second  and  third  columns,  approximately 
satisfv  the  relation 
Katio  N0  :  0, 
Ratio  N2  :  02  in  liquid 
■£Z^r  =  6.60  -0-028  m=C, 
where  m  is  the  molecular  percentage  of  nitrogen  in  the  liquid. 
Similarly  in  Table  III.  the  value  of  this  same  quotient  is 
5*48—  0'0207  m.  Now  by  means  of  these  formulae  we  can 
calculate  the  composition  of  the  vapour  from  the  composition 
of  the  liquid,  and  these  results  are  given  in  the  fourth  column 
of  the  tables  under  the  heading  "  nitrogen  in  vapour  calcu- 
lated." It  will  be  seen  that  the  differences  from  the  observed 
values  are  slight  except  when  the  value  of  m  is  small.  Now 
in  this  case  an  error  of  0*1  per  cent,  in  the  liquid  corresponds 
