224 REPORT UNITED STATES GEOLOGICAL SURVEY. 



1877. — General Sherman visited the Upper Geyser Basin in 1877, and 

 speaks of Old Faithful as follows : 



We readied the Upper Geyser Basin at 12 noon one day, and remained there till 4 

 p. m. of the next. During that time we saw the Old Faithful perform at intervals 

 varying from 62 minutes to 80 minutes. The intervals vary, but the performance only 

 varies with wind and sun. * " * So regular are its periods of activity that we 

 could foretell its movement within a few minutes ; sometimes we stood near enough 

 to feel the hot spray, and at others we sat at our camp, about 300 yards away. Each 

 eruption was similar, preceded by about 5 minutes of sputtering, and then would arise 

 a column of hot water, steaming and smoking, to the height of 125 or 130 feet, the 

 steam going a hundred or more feet higher, according to the state of the wind. It 

 was difficult to say where the water ended and steam began, and this must be the 

 reason why different observers have reported difierent results. The whole perform- 

 ance lasts about 5 minutes, when the column of water gradually sinks, and the spring 

 resumes its normal state of rest.* 



Colonel Poe sayst that seven eruptions were observed, varying from 

 62 to 80 minutes, with an average period of about 67 minutes. 



1878. — The eruiJtions noted by us were exactly like those seen by us 

 in 1871 and 1872, and as observed by others. We were fortunate in ob- 

 taining a large number of its intervals, which are given in the following 

 table. I am indebted to almost every member of the party for observa- 

 tions made while I was in other i^ortions of the Basin. The heights are 

 the heights of the column of water, and were obtained from angles taken 

 with the gradienter, and the reason we took so few comparatively is 

 due to the fact that the instrument was used a large i^art of the time in 

 the tri angulation : 



* General Sherman's tour of inspection, &c., in reports of inspection made in the 

 summer of 1877. Washington, 1878, p. 36. 

 ilbid., p. 78. 



