PEALE.] 



SHOSHONE GEYSER BASIN UNION GEYSEE. 



259 



by intervals of about 3 and 7 liours. After the fifth eruption we ex- 

 pected one about 6 or 7 o'clock in the evening, but it did not take place, 

 nor did one take place on the 26th as we expected. It is probable, 

 however, that if the observations could have been carried on long enough 

 a regular irregularity would have been observed, i. e., the law of the 

 irregularity would be determined. 



In the interval between eruptions 1 and 2, and 2 and 3 and between 

 4 and 5, the craters remained empty, while during the five days inter- 

 vening between 3 and 4 the cones, or craters, gradually filled. ISTos. 1, 

 2, and 3 ought, therefore, to be considered as different periods of the 

 same eruption, and 4 and 5 as periods of another. 



Twenty-four hours and fifteen minutes after the first eruption began 

 water was observed at the base of the central crater ; and at the end of 

 2 days and 10 hours it was within 2 feet of the top. 



After the second eruption (No. 4 in the table) it was also 24 hours 

 and 14 minutes after the beginning before the water was noticed at the 

 bottom of the central cavity, and 2 days and 10 hours when it was with- 

 in 2 feet of the top. For more than a day preceding the action of the 

 geyser the water is in violent agitation and spurts several feet above 

 the cone. Too few eruptions were seen to enable us to determine the 

 length of this period of agitation. If it had been seen only when in 

 this condition it might have been classed with those springs that are 

 constantly agitated. It is probable that many of the springs so classed 

 may be true geysers with long intervals. In most cases, however, the 

 appearance of the surrounding deposits will enable one to judge of the 

 character of the spring. 



The discrepancy in the two tables just given as to the total length 

 of the eruption is probably due to the uncertainty as to when it is ended, 

 as the alternation of puffs and quiet periods decline so gradually that it 

 is difficult to determine the exact end of the eruption. In eruptions Xos. 

 1 and 4, which were really the beginnings of two separate eruptions, the 

 steady roaring was marked; but in Nos. 2, 3, and 5 there was a marked 

 difference, periods of perfect quiet distinguishing them very soon after 

 the eruptions began. 



The temperatures were taken with a maximuYn self-registering ther- 

 mometer, which was placed at the end of a graduated pole. 



TaMe of temperatures of Union Geyser 



taken 



in 1878. 









Center-cone. 



North cone. 



Vent. 



South 

 cone. 



Date. 



i • 







o 



? 3 



"a 6 

 m 



o 



IS 





© 



© o 

 H 



a . 



© © 



It 



t! P. 



a 



CO 



o 



© r) 



o 



■© © 



6 

 o 



<6 



o 



1 



AufTUst 17 : 

 2.30 p. m 



OF. 

 190 



198 



O J-. 



201 

 204 



o p. 



o p. 



cp. 



o Y. 



o Y, 

 63 



60 

 60 



55i 



60 



57 



58 

 58^ 



57 

 61J 



4Ci 



o Y. 

 197 



196 



Y. 

 197 



198 

 air, 62 



y. 



o -p. 



Aupnst 18 : 



11.30 p. m 



204 









'"'igi' 





3.00 p. m ... . 



205 









Aupust 19: 



8 40 a. m 



197i 



198 



200 



200 

 199 



199 

 198 



199 









205 











194 



1.00 p. m 









207 

 208 



208 

 208 













6.40 p. m 



















August 20 : 









198 





204 







C 30 p. m 













August 23 : 





206 

















207 

















August 25: 

 8.00 a m 









207 

































