AND ON THE LAW OF PEES.SURE OF CJA8E8, ETC. 
217 
nitrogen, extending over ten days, the zero varied from 43’5 to 43'S. Whenever 
possible the zero used for a set was the mean of values found before and after. 
The annexed tables give the results for nitrogen in detail. In Table I., dealing 
with the highest quantity of gas, the first column gives the volume (V = 45‘6 cub. 
centims.); the second represents the pressure, being tlie mean of the two actually read 
numbers (exjDressing millimetres of telescope scale) less the zero reading 437 and 
corrected to infinitely small arcs as already explained. The third column is the 
logarithm of the product of the first two, and should be constant if Boyle’s law 
holds. The fourth column gives the approximate value of the pressure in millimeti’es 
of mercury ; the fifth the deviation of jw from the mean taken as unity. In the 
sixth column is shown the amount by which the ol)served value of p exceeds that 
requisite in order to make pv constant, expressed in millimetres of mercury. 
Table I. — Nit rogen. 
November 9-11, Zero = 437. 
Volume in 
cub. centims. 
Pressure in 
scale divisions. 
Log. pioduct. 
Pressure in 
millims. FW. 
O 
Deviation 
of pr. 
Error of p 
in millims. 
V + 70 
345 • 4 
-G013 
1-49 
+ -0002 
+ -0003 
V + 80 
318-3 
-G018 
1-38 
+ -0014 
+ -0019 
V + 90 
294-1 
-6007 
1-27 
- -0012 
- -0015 
V +110 
25G-8 
-601G 
1-11 
+ - 0009 
+ -0010 
V +130 
227-4 
-6013 
-98 
+ -0002 
+ -0002 
Y +150 
203-7 
-6004 
-88 
- -0018 
- -0016 
V +170 
184-9 
- 6005 
-80 
- -0014 
- -0011 
V h-190 
1G9-8 
-6021 
-6012 
’ 7 3 
+ -0021 
+ -0015 
Table II.—Nitrogen. 
Novemljer 11-12, Zero = 437. 
Volume in 
; cub. centims. 
1 
I’ressurc in 
scale divi.sions. 
Log. product. 
Pressure in 
millims. Hg. 
1 )eviHtion 
of pr. 
Eii'or of ji 
in millims. 
1 V + 0 
344-9 
-1966 
1-49 
+ -0007 
+ -0010 
1 V + 10 
282-3 
-1958 
1-22 
- -0012 
- -0015 
V + 20 
239-5 
-1962 
1-04 
- -0002 
- -0002 
i V + 40 
183-3 
-1956 
-79 
- -0016 
- -0013 
V + 60 
148-8 
-1963 
-64 
-0000 
-0000 
j A + 80 
125-2 
-1966 
-54 
+ -0007 
+-0004 
V+110 
101-1 
-1968 
-44 
+-0012 
+ - 0005 
I V+150 
80-2 
-1955 
- 35 
- -0018 
- -0006 
j V +190 
66-9 
-1976 
-29 
+ - 0030 
+ - 0009 
-1963 
VOL. CXCVI.—A. 2 E 
liL 
