364 
DR. MEYER WILDERMAN OX CHEMICAL DYXAMICS 
capillary of the manometer was only a few tenths per cent, of the volume of the gas 
in the reaction vessel immersed in the bath, so that if the differences between the 
temperature of the room and that of the bath were very great a small correction 
was necessary. 
Two mercury thermometers were immersed in the bath, one divided into degrees 
centigrade which could be read to 0°'l, and the other a 0°T thermometer of 
Beckmann’s type, with divisions about 3 millims. apart from one another, allowing the 
temperature of the bath to be read to 0 C- 01. The thermometers were kept very near 
to the reaction vessel; the temperature of the gaseous mixture in the reaction vessel 
with the quartz windows was indicated by the iron-nickel thermocouple inside the 
same. Later on the temperature was calculated, no thermocouple being employed, to 
ensure the gaseous mixture not being contaminated with any traces of other substances 
during the reaction. Near the capillary tube of the manometer was a thermometer, 
divided into degrees centigrade to indicate the temperature of the room. 
To keep the temperature of the bath constant at any desired temperature, the 
copper bath was large, containing about 70 litres of water. It was covered with 
very thick sheets of asbestos, placed in a wooden box with an air space between it 
and the sides of the box, which was jffaced in another wooden box with another air 
space between them, while the top of the bath was covered with a wooden lid. At 
the bottom a small circle was cut out of the wood and asbestos for a rose burner 
2 centims. distant from the exposed circle of the copper bottom. The temperature of 
the bath itself regulated the supply of gas to the burner. The liquid was thoroughly 
stirred at frequent intervals. Since with all these arrangements the temperature of 
the bath could not be kept sufficiently constant, owing to the heat absorbed from the 
powerful acetylene light, the temperature of the bath was adjusted to the desired 
degree by melting ice, especially when the temperatures required were below 25° or 
30°, and by thorough stirring. In this manner the variations of temperature of the 
bath were kept within as narrow limits as possible during the whole time of the 
experiment. Each time the readings of the manometer and of the temperature of the 
hath and of the reaction vessel had to be made, the bath was effectually stirred, 
readings being taken two minutes later. During this period of two minutes the 
temperature of the bath near the quartz vessel does not rise under the action of the 
light more than 0 C, 01. Since for our purpose it is important to know the difference of 
the temperature of the gas mixture at two different times, so as to be able to apply the 
necessary correction, the above manner of making the readings each time two minutes 
after the bath was well stirred, eliminated the error in the determined differences of 
temperature almost completely. An investigation of the velocity with which the 
mercury of the manometer assumes its maximum when the glass bulb or quartz 
vessel is immersed in the bath showed that after two minutes the temperature of the 
gas in the bulb is much less than 0°’0J removed from the convergence temperature, 
the amount of our reading error. This convergence temperature of the gaseous 
