PEALE.J 



UPPER GEYSER BASIN GRAND GROUP. 



215 



The following table shows the periods as nearly as they can be deter- 

 mined : 



Eruption. 



Periods. 



Duration. 



Intervals. 



Maximnm 

 height. 



Eemarks. 





No. 

 1 

 2 

 3 

 1 

 2 



3 



1 

 2 



3 



1 



2 



5 or 6 



1 

 2 



3 



m. s. 



700 

 1 45 

 1 30 

 9 00 



1 30 



2 30 



8 30 



3 23 



5 00 



8 30 

 (*) 



(t) 



9 00 



3 25 



20 



m. 8. 



Feet. 







45 

 4 45 





















1 00 



2 00 





In the second period there were 

 two spurts. 



In the third period there ^ere 

 three spurts with the follow- 

 ing intervals, 1". 45n and 

 Ora.45^ 



Third . . 



165 





22 



1 30 





In the second period there were 



three spurts with intervals of 



1'". 83^ and l-". 45». 

 They lasted only a few seconds, 



the last one 5». ; one spurt in 



third period 5^ long. 







Fourtli 



95 





3 00 



One spurt in second period. 

 I could not determine spurts 

 from periods. 



Fifth 





Sixth 









CO 15 

 2 20 





Three spurts in second period, 

 with intervals of 1". 35'., 1™. 

 10'. and 0". 40^ 



Two spurts in last period, in- 

 terval of 0">. 20'. 











* One spurt not timed, t Not taken. 



The fourth eruption was noted by Mr. Ladd, and the measured height 

 was not of the highest eruption which was attained in the last spurt, 

 and was so much obscured that he could not take the angle. The in- 

 strument was not set n\) when the first and third eruptions were noted, 

 and when the fifth and sixth occurred it was too dark to read the angles. 



A comparison of the tables that I have given seems to indicate that the 

 Grand is very irregular in its action ; but we must remember that the 

 observations are not consecutive over a long time, and until they are 

 carried through at least a period of several months consecutively we 

 cannot predicate anything as to the laws of action it has. What now 

 appear to be irregularities may recur at regular periods. We know very 

 little also as to the effects of the varying sui)plies of water that may 

 occur at different seasons. It is to be hoped that at some time a party 

 will be stationed on the Upper Basin to carry on observations extending 

 through several consecutive seasons. An eruption of 10 minutes' length 

 was noted from a distance at 6.40 p. m. on the evening of August 26. 

 It is not included in the table, as we could not be absolutely certain 

 of its being the Grand.* 



* The following observations on the Grand Geyser is taken from Mr. P. W. Norris' 

 Report for 1881, p. 56 : 



Date. 



Time of eruption. 



Duration 

 of eruption 

 in minutes. 



Height of 



the column 



of water in 



feet. 



Eemarks. 



1881. 

 Oct. 4 



9.45 a. m 



20 

 25 

 20 

 20 

 20 



200 

 200 

 20fl 

 200 

 200 





4 





water at all of these eruptions was vorti- 

 cal and of remarkahlo symmetry and 

 heauty. 



5 



3.25 p. m 



6 



9.15 a. m 



C 



4.20 p. m 









