March, 1919] Temperatures of Ten Thousand Smokes 255 



The same thing was apt to happen if the two wires were 

 allowed to rest on the wet ground, as the steam usually kept 

 the ground around the fumaroles damp. We therefore sup- 

 ported the wires on some object, such as a spade or a pole. 

 The porcelain tubes, too, would sometimes collect the con- 

 densed steam and short circuit the instrument. As the two 

 wires went through perforations in the same tube, the only 

 remedy for this was to allow them to dry out again if they 

 became saturated with water. This was usually accomplished 

 by allowing the thermocouple to remain in some hot fumarole 

 for a considerable length of time. As one had to thrust the 

 wires from the cold air into the hot steam, more .or less con- 

 densation always occurred. If the fumarole was above 200 C. 

 the condensation would not be very great and the tubes would 

 quickly dry out, but if it was just above the boiling point, so 

 much water would condense that we would get a temperature 

 of only 100 C. As a result, we obtained very few temperatures 

 just above the boiling point, because we did not wait long 

 enough for the tubes to dry out or because the temperature was 

 not high enough to dry them out. Out of the 48 fumaroles, 

 or areas of fumaroles, we studied, only six were found which 

 registered between 100 C. and 190 C. 



Many of the fumaroles of the Valley were inaccessible to us 

 with the instruments which we had. The thermocouple of 

 the pyrovolter, which was six feet long with 50 feet of lead wire, 

 was made of such small wire that it would not support its own 

 weight, so we had to attach it to a long pole. This complicated 

 matters considerably, for if we used wire to fasten it on, the 

 insulation would quickly burn through in hot fumaroles and 

 short circuit the wires, and if we used string, rope or something 

 of that nature, it was very soon burned off. Besides, the pole 

 served as a collector of steam and, although the wires did not 

 touch, they were short circuited by the steam, especially at 

 the point of contact of the cool air and the hot gases. The only 

 practical and satisfactory way in which we could use this six 

 foot thermocouple was for lone fissures or cracks not sur- 

 rounded by an area of steam, where the temperature at the 

 surface or six inches down was required. It was in these places 

 that we used it to check up the readings of the pyrometer. 



The thermocouple of the Ho'skins pyrometer was 10 feet 

 long with 30 feet of lead wire. At the end used in the hot gases, 



