256 EEPOET UNITED STATES GEOLOGICAL SURVEY. 



which had ceased at 7 o'clock. At 7.05 p. m. the steam issued from the 

 crater in pulsations at the rate of about 79 per minute. At 7.30 p. m. 

 the i)ulsations were irregular and the intervals between them growing 

 longer. At 7.50 p. m. the pulsations are about 16 to the minute, and 

 thesteam very much diminished in amount; at 8.05 p. m. they are very 

 faint, and at 8.10 about ended. In the south cone, except at the very 

 beginning of the steam period, the steam escajjes gently. During the 

 eruption the Impenetrable Spring was quiet. At 9.35 p. m. another 

 eruption began, which resembled the one just described, except that at 

 9.52 there was a decided lull of a minute, after which the steam escaped 

 in pulsations, followed at 10.10 p. m. by another stop. This was repeateil 

 until the end of the eruption, which lasted about an hour. 



August 16. — 3.40 a. m. an eruption began followed in about 10 minutes 

 by a stop, after which steam escaped in pulsations as in the preceding 

 eruption. The time of stoppage was not taken. At 6 a. m. the craters 

 were found to be empty, and remained so during the day. From the 

 central cone there was a slight escape of steam. At 7 jj. m. water could 

 be seen in the tube below the globular chamber of the central crater. 



August 17. — Early this morning the water is in sight in the center 

 crater. At 2.30 p. m. the following temperatures were taken. 



Center cone : At surface of water, which is 4 feet below the top of the 

 cone, has a temperature of 196° F. j 2 feet below the surface of the water 

 the temperature is 201° F. 



North cone: At surface of water, which is 3 feet below the top, the 

 temperature is 197° F. ; 1 foot below the surface it is 198° F. The tem- 

 perature of the air during these observations is 630° F. In the south 

 cone the temperature could not be taken. 



August 18. — Center cone: At 11.30 a. m. the water is within 2 feet of 

 the top, and the temperature at the surface is 198° F. Two feet below 

 the surface the temperature is 200° F.j at 4 feet it is 204° F., and at 5J 

 feet the same, the temperature of the air being 60° F. 



North cone : At 12 m. the water is within 1 foot of the top, and the sur- 

 face temperature is 196° F., and 2 feet below it is 197° F. 



In the south cone the water is too low to take the temperature, while 

 in the smaU opening between the central and south cones the tempera- 

 ture is 1910 F. 



Center cone : At 3 p. m. the water is still 2 feet below the top, and 

 the temperature 5 feet below the surface is 205"^ F., the air being 60° F. 



August 19. — Center cone : At 8.40 a. m. the water is within a foot and 

 a half of the top, and has a surface temperature of 197^° F., and at a 

 depth of 6^ feet it is 205° F. It boils violently and there are occasional 

 spurts over the edge. At 1 p, m. the water is within a foot of the top, 

 with a temperature of 198° F., while 6 feet below the surface it is 

 207° F J temperature of air 55° F. At 6.40 p. m. the water is within 6 

 inches of the top, and at intervals spouts over the edge ; the surface 

 temperature is 200° F., and at 6 feet below it is 208° F. At 9 p. m. 

 splutters and splurges with great noise. 



North cone : At 8.40 a. m. the water is within 2 inches of the top and 

 comparatively quiet, only a few bubbles occasionally escaping. It over- 

 flows at 6.40 p. m. 



South cone : The water rises and falls in pulsations.. The tempera- 

 ture is 194 at 8.40 a. m. In the vent between the center and south cones 

 the water also pulsates. 



August 20. — Center cone : At 8.25 a. m. the water boils vigorously, 

 spouting over the edge. The surface temperature is 200° F. ; 6 feet be- 

 low surface, 208° F. This spouting kept up during the day, and the tem- 

 peratures at 6.30 p. m. were, at the surface, 199° F., and 6 feet below, 208° F, 



