98 



EEPOET UNITED STATES GEOIiOGICAL SURVEY. 



11.49 a. m. — The water is rising slowly. 



2.39 p. m. — The water is within 1 foot of the top of the basin and bubbling in the 

 center. Its temperature near the edge is 146° F., the air still being 60° F. 



3.14 p. m. — Temperature outside the rim of the basin is 125° F. 



3.15 p- m. — The eruption commences. 

 3.21 p. m.— There is a lull. 



3.25 p. m, — The maximum (22 feet) is reached. 



3.27 p. m. — The eruption ends. Temperature of water at edge of basin 170° F. 



7.39 p. m. — The eruption commences. 



7.44 p. m. — There is a lull. 



7.48 p. m. — The maximum (19 feet) is reached. 



7.51 p. m. — The erui)tion ends. 



Mr. Sloane took observations of two eruptions on August 9, as follows: 



12.40 p. m. — Eruption commences. 



12.47 p. m.— Lull. 



12.49 p. m. — Maximum estimated at 25 feet. 



12.52.30 J), m. — Eruption ends. 



4.58 p. m. — Eruption commences. 



5.04 p. m.— Lull. 



5.07 p. m. — Maximum estimated at 30 feet. 



5.11 p. m. — Eruption ended. 



The table following is practically the same as that given in the report 

 for 1872, the difference being that the one now given contains some 

 additional i)oints not included in the one for 1872 : 



Date. 



a 



o 



1 



o 



6 



|2i 







° 2 



§ 



£ o fl 

 a 



H 



a 



^5 a 



a 



M 



PI'S 

 © 



"S Mm 



© 2 fc) 





 H 



Interval between 

 end of one and 

 beginning of 

 next eruption. 



-t5 



s 

 a 

 a 

 1 



Temperatures. 



1872. 



1 



2 

 3 

 4 

 5 

 6 

 7 

 8 



M.S. 



12 30 



13 00 

 13 00 

 13 00 



11 00 

 13 00 



12 00 

 12 00 



M. 

 6 

 6 

 6 



M. 

 3 

 3 



4 



S. M. S. 



H. M. S. 



Feet. 

 25 

 30 

 40 

 20 

 25 

 18 

 22 

 19 



o p^ 



9 



4 18 00 



4 05 30 





11 



180 just before. 



11 



4 31 00 



4 18 00 



12 



4 

 6 

 6 

 5 







12 



3 



4 

 4 



4 20 00 

 4 2C 00 

 4 24 00 



4 07 00 

 4 13 00 

 4 12 00 



180 j'ust before. 



12 



12 









Comparing this with the table for 1871 it will be seen that the length 

 of the eruption is less by several minutes (2 to 5) and that the intervals 

 between the eruptions is greater. 



The following table compares the averages of the two years : 



1871. 



1872. 



Average lengtli of eruptions 



Average intervals between ends and beginnings. 



15m..37is. 

 3h. 15m. 



12m. 26. 75s. 

 4/1. llm.es. 



It must, however, be remembered that these averages are derived from 

 comparatively few observations. 



1873. — As far as I can learn no observations were made in 1873, as 

 Professor Comstock passed down the right bank of the river and did not 

 therefore see the " Mud Geyser." 



1874. — The Earl of Dunraven saw two or three eruptions, but gives 

 no particulars,* except to say that they lasted about 10 minutes and 



* The Great Divide : Travels in the Upper Yellowstone in the Summer of 1874, by the 

 Earl of Dunraven, London, 1876, p. 247. 



