I 
1)];. M. TRXYER<, MR. G. SI-:XTER, AXD DR. A. JAQTMT.OD 
Previous XfrasureuKoits of the Vapour Pressures of LirpAid Oxyejen. 
The earliest iiieas\ii-einent to ^^llich any importance can he attached is that 
of Wnon-LEWSKi in 1 888 (‘'Wiener Berichte,’ ‘J7, Abth. 2 a. p. 1321). The teni- 
]»ei'atnre of the hoiling-poiiit of exygen was measured on the constant-volume 
hvdrttgen scale, hut no details are given in the paper, which is entitled “ Die 
Zusanimeudrnckharkeit des Wasserstoffs,” and was published after his death. The 
number oiven bv him is 182'4° ('. 
Olszewski ajipears to have measured the boiling-point of oxygen on several 
occasions. In 1800 he published in ‘Nature’ (vol. 54, 377) an account of his com¬ 
parison of the hydrogen and helium thermometers at temperatures corresponding to 
\apour pressures below 741 millims. mercury. By extrapolation the temperature of 
the boiling-point on either thermometer appears to he — 182’3G° Cf In his paper on 
the licpiefaction of gases (‘ Phil. Mag.,’ 1805, vol. 30, p. 188) he gives — ]8L'4° as the 
l)oiling-point. The capacity of the hull) of his thermometer was only 2 cub. centims. 
Kstp.ek'IIEU (‘ Phil. Mag.,’ (5), vol. 40, p. 454) also made a large number of measure¬ 
ments. He made tu'enty-tive measurements of the temperature corresponding to 
744'8 iihllims., and gives —182'50°CA as tlie mean of the results. The boiling-point 
calculated by extrapolation is — 182'4° Cf (aT being 0'0122*^ per millimetre). 
Estreilheu worked in ( Ilszewski's laboratory, and employed the same instrument 
as the latter. 
AVitkowskj (‘ Phil. Mag.,’ 1806, vol. 42) gives the boiling-point of oxygen as 
— 182’44G^O., employing the value 0’003GG for the coefficient of expansion of 
hvdroo-en. 
a O 
Holborx and W^iex (‘ Wied. Ann.,’ 180G, vol. 50, p, 213) compared the hydrogen 
and air thermometers at the tem})erature of liquid air, and found that the readings 
of the air thermometer were 0'G5' lower than those of the hydrogen thermometer. 
Later, HoLBOiix (‘ Ann. der Pliysik,’ (4), 1001, vol. G, p. 242) staiidardised a })latinum 
resistance tliermometer by means of an air thermometer, and by means of it measured 
the boiling-point of ])Ui‘e oxygen. The tem])erature referred to the constant-volume 
hvdroiren scale is — 182'7’(f Pull details of the Avork, AA’hich Avas carried out in the 
I’hysikalische Beichsanstalt at Dharlottenburg, are given in the paper. 
Ladexburg and Krugel ('Ber.,' 1000, axaI. 32, p. 1818, Ami. 33, p. G37) found — 182‘2^ 
fi»r the tenq)erature coiTesj)onding to a pressure of 745 millims. (boiling-point 
— 182'05°(J.). Tlie measurement aa'rs made by means of a thermo-electric junction, 
standardised at the temperature of liquid air, AAdiich aaxis siqiposed to be — 101’25d 
Deavar (‘Proc. Poy. Soc.,’ 1001, Ami. G8, p. 44), employing constant Amlume 
thermometers filled Avilh hvdroo’en and oxA'iren, obtained the folloAvinq' Amines. The 
munbers in third value of the following table are calculated from the mean value 
()f djfalf. 
