284 J. W. Gibbs — Vapor- Densities. 
Peroxide of nitrogen.—If we take the constants of the equa- 
tion for this substance from the paper already cited,* we have 
15°89 (D — 1°589) 3118°6 
log = —— — 12°451 10 
©. (3178 — D)" to + 278 + log p — 12°451, (10) 
each series the experiments were made with increasing temper” 
atures, and with the same vessel, without refilling. Tt should 
e observed that the results of the three series are not rega 
what larger values, with a single exception, as is best seen. i 
the columns which give the excess of the observed density. 
ular to be attributed to the accidental errors of the individual 
observations, except in the case of the experiment at 1518; 
* See equation (336) on page 339, loc. cit.,—also the following equations 1 
which "3 density is given in terms of the temperature and pressure. In — 
ti 
se 
measured in atmospheres, but in this paper in millimeters of mercury. 
nm assumed as the pressure of the atmosphere in all cases 
= difference of 13 millimeters in the pressure would in nO ~ 
reg a difference of -005 in the calculated Pte In this series, the 
‘i due to this circumstance are not very serious. 
ogg. Ann., vol. xxix (1833), p. 220. 
Lieb. Ann., vol. cxxii (1862), p. 15. 
Comptes Rendus, vol. lxiv (1867), p. 237. 
