DAY AND shepherd: WATER AND MAGMATIC GASES 4(51 



quantity as seriously to affect if not to determine the temperature 

 of the whole mass. This chemical activity will be a maximum 

 at the surface at the moment of discharge into the atmosphere 

 and the proportions of the reacting gases will vary with every 

 bubble which bursts from the liquid lava, as is plainly shown by 

 the variations from one tube to another in the above analyses. 



It would seem to be a necessary consequence of this mode of 

 release of the gases previously in solution and the resulting exo- 

 thermic reactions between the gases after release, that the tem- 

 perature of the lava lake should rise when the quantity of gas 

 given off is large, and should diminish again when the gaseous 

 exhalation diminishes in volume, and this was found to hold true 

 thruout the activity of the summer of 1912 of which we were 

 witnesses. The measured changes in temperature in the lava 

 basin in this interval of about four months (the quantity of lava 

 in the basin remaining practically constant) amounted in maxi- 

 mum to 115° (June 13, 1912, 1070°; July 6, 1912, 1185°). 



(2) The exhalation unquestionably contains water, of which 

 about 300 cc. were found condensed in our tubes. In view of the 

 fact that the water condensed and remained behind while the 

 fixed gases passed on thru the tubes and pump, it is not possible 

 from these observations to estimate the proportion of water to 

 the fixed gases. 



(3) The presence of free S, SO2 and SO3 in the cloud affords 

 adequate explanation of the phenomena observed by Brun. The 

 visible cloud consists mainly of free sulfur (not of chlorides) and 

 we were able to collect it from the cloud, both at the point of 

 emergence and at the crater rim where Brim's observations were 

 made. It follows from this that the cloud would not evaporate 

 in the air nor show optical phenomena (rainbows), neither could 

 it be expected to condense upon the crater walls, nor in tubes, if 

 the point of collection was too far away from the point where the 

 gases were released from the lava. The observations of fact made 

 at Kilauea by Brun are for the most part confirmed by our 

 observations, but we were unable to discover in them any basis for 

 his conclusion that the exhalation is anhydrous, for the tiny sulfur 

 particles would supply abundant nuclei of condensation for any 



