AND ON THE LAW OF PKESSHEE OF 
GASES, ETC. 
22? 
Table 
IX.- 
—Oxygen. 
Pressure in 
Deviiitioii 
Error of p 
Pressure in 
Deviation 
Error of p 
millims. Hg. | 
of pv. 
in millims. 
II 
millims. Ilg. 
oipv. 
in millims. 
1-53 
+ -0016 
+ -0024 
•580 
--0035 
- -0020 
1-17 
- -0012 
- -0014 
•472 
+ •0005 
+ -0002 
, -95 
+ -0005 
+ -0005 
■396 
- -0007 
- -0003 
' -80 
+ -0007 
+ -0006 
-.321 
+ -0016 
+ •0005 
• 65 
+ -0012 
+ -0008 
•255 
+ -0012 
+ -0003 
•57 
- -0009 
- •0005 
•’21'^ 
+ -0010 
+ -0003 
•51 
- -0014 
- •0007 
— 
— 
•47 
- -0014 
- -0007 
— 
— 
— : 
•43 
+ -0009 
+-0004 
— 
— 
•288 
+ -002 
+ -0007 
•142 
+ • 005 
+ -0007 
•233 
•000 
•0000 
■115 
+ -009 
+ -0011 
•196 
•000 
•0000 
•094 
- -019 
- -0018 
•159 
+ -005 
+ -0008 
•077 
•000 
•0000 
•125 
- -002 
- -0003 
•062 
+ -012 
+ -0007 
•103 
- -009 
- -0010 
■051 
- -012 
- -0006 
•068 
- -002 
- -0002 
■034 
■000 
• 0000 
•056 
+ -005 
+ -0003 
•029 
+ -059 
+ -0017 
•048 
+ -019 
+ -0009 
•022 
- -042 
- -0009 
•038 
+ • 009 
+ -0004 
■019 
+ -023 
+ •0004 
•029 
- -019 
- -0005 
•014 
- -035 
' • - • 0005 
• 025 1 
- -009 
- -0002 
— 
— 
The hiial result uf the ohservatioiis on tlie three gases may 1)e said to 1)6 tlie full 
confirmation of Boyle’s law between pressui-es of I'o millims. and '01 millim. of 
mercury. If there is any doubt, it relates to the case of hydrogen, wliich appears 
to press somewhat in excess at the highest pressures. But when we consider the 
smallness of the amount and the various ctanplications to ^^'hich it may be due, as 
well as d priori probabilities, we may well hesitate to accept the departure from 
Boyle’s law as having a real existence. 
So far as the })resent results can settle the (juestion, they justify to the full the 
ordinary use of McLeod’s gauge within the limits of pressure mentioned and for 
nitrogen and hydrogen gases. The same might he said for oxygen ; l)ut until the 
discre})ancy with the conclusions of Bohr can l)e explained, tlie necessity for some 
reserves must he admitted. 
In any case tlie new manometer lias done its work successfully, and is proved to 
he capable of measuring small ])ressures to about of a millimetre of mercury. 
It was constructed under my direction by Mr. GoRiDOX. 
