Chemistry and Physics. 63 



below that of ethylene. Hence it should liquefy at the atmos- 

 pheric pressure if the temperature was sufficiently low. At the 

 temperature of —150° no liquefaction occurred, no doubt because 

 of the large amount of oxygen mixed with the ozone. But at 

 — 181 '4, the temperature of boiling oxygen, the condensation 

 readily took place and the dark blue liquid was produced. In 

 very thin layers at this temperature it is transparent, but in layers 

 2 mm thick it is nearly opaque. On introducing the tube contain- 

 ing it into liquid ethylene at — 140°, the ozone remained liquid, 

 beginning to vaporize when the temperature of the ethylene -had 

 risen to near its boiling point. By means of a thermometer, con- 

 taining carbon disulphide, the temperature* of the ethylene was 

 fixed. At the moment of incipient ebullition of the ozone this 

 thermometer indicated a temperature of — 109°, corresponding 

 on the hydrogen thermometer to — 106°. Hence this value may 

 be taken as the boiling point of liquid ozone. Sealed in a glass 

 tube the liquid becomes a blue gas, which may be again con- 

 densed by placing it in boiling ethylene. Since a violent explo- 

 sion ensues if the liquid ozone is allowed to come in contact with 

 ethylene gas, great care is necessary to prevent this from taking 

 place. Ethylene itself solidifies in boiling oxygen and fuses again 

 at —160°. — Wien Monatch. f. Chem., viii, 69; Ber. Berl. Ghem. 

 Ges., xx, Ref. 245, May, 1887. ' g. f. b. 



2. On the Absorption-spectra of liquid Oxygen and of lique- 

 fied Air. — Olszewski has examined the absorption-spectrum of 

 liquid oxygen, employing solar light for this purpose. Using a 

 small direct-vision spectroscope, two strong dark lines were ob- 

 served in the o range and yellow, which did not entirely disappear 

 when the oxygen was all volatilized, and which were found to be 

 present in the ordinary solar spectrum, faint at midday, but dis- 

 tinct at sunset. With greater dispersion, the oxygen lines ex- 

 panded into bands resembling the telluric bands of the sun spec- 

 trum ; remaining visible when electric or calcium light was 

 substituted for sunlight. On increasing the layer of liquid oxy- 

 gen from 7 mm in thickness to 12 mm , two more bands appeared; a 

 faint one in the green and a stronger one in the blue. The wave- 

 lengths of these four bands, measured from the central line, were 

 628, 577, 535 and 480 millionths of a millimeter. The first of 

 these bands is distinguished by its breadth, the second by its 

 intensity; the last two bands, which are more feeble, do not 

 appear in the sun spectrum. The air, whose spectrum was exam- 

 ined, was carefully freed from moisture and carbon dioxide before 

 liquefaction. No new bands appeared, the spectrum consisting 

 mainly of the bands 628 and 577, above mentioned, which were 

 faint. They became stronger as the liquid became richer in oxy- 

 gen by the evaporation of the nitrogen mixed with it. Of the 

 four telluric bands in the sun spectrum A, B, a and d, which 

 Angstrom has shown cannot well be due to aqueous vapor on 

 account of their stability, the two latter coincide with the two 

 strongest of the above oxygen bands. Egoroff concluded from 



