J. C. Graham— Experiments with an Artificial Geyser. 57 



this means the error is made a nearly constant one, and the 

 height of the column is not affected. 



The question of a constant supply of heat cannot be entirely 

 solved, or at least could not be with the apparatus at my con- 

 trol. But by the aid of the self- regulating gas-cock I was 

 able to keep the supply nearly constant, and by means of 

 many readings of the thermometer immersed in the mercury 

 bath, a comparison could be made in the cases of different 

 eruptions which I think are sufficiently accurate and definite. 



The error of barometric pressure variations was overcome 

 by making observations on various days and comparing those 

 in which the heights of the mercury columns were nearly the 

 same. 



There were also many minor factors, such as the temperature 

 of the room in which the observations were made, which had 

 to be taken into account and eliminated when possible. 



In making the statement of the results of these experiments, 

 only a few from several hundred observations will be given ; 

 those in which the various conditions were most favorable to 

 accurate determinations. In Tables I and III the fluid used 

 was ordinary water from the city reservoir. In Tables II and 

 IY it was a solution of Ivory soap in water, of such strength 

 that it was of a molasses-like consistency when cold, but of 

 course much more fluid when warm. 



reinpera- Temp, 

 ture of Hg. at 

 room. erupt. 



Temp. 



Hg-. after 



erupt. 



Temp, 

 aq at 

 erupt. 



Temp. 



aq_ after 



erupt. 



Time of erupt 

 H. M. S. 



Period between 

 erupts. 



Water. 







I. 



Barom 



30-24 in. 



21-5° 107-5° 



104-5° 



103-2° 



94° 



11 35-25 



6-30 



21-5 107-5 



104 8 



103-2 



94 



40-25 



5-25 



21-5 1072 



104-5 



103-2 



95 



46-30 



. 6-05 



215 107-2 



1045 



1032 



95 



52-50 



6-20 



215 107-2 



104-3 



103 2 



94 



59-15 



6-25 



Soap and Water. 







II. 



Barom. 



SO- 2 



22 107-5 



104-7 



103 



91-5 



14- 



5-15 



22 5 107 



104-7 



103 



91-5 



19-10 



5-10 



22-5 107 



104-6 



103 



91-5 



24-20 



5-10 



22-5 107 



104-7 



103 



91-5 



24-55 



5-35 



22 107 



104-6 



103 



91-5 



35-10 



5-15 



22 107 



104 + 



103 



91-5 



40-20 



5-10 



Water. 







III. 



Barom. 



29-74 



22 106-5 



103-8 



103-1 



94 



] ° 21-05 



7-50 



22 106-5 



103-5 



103 



93 



29 



7-55 



22 106-5 



103-8 



103 



94 



37-10 



8-10 



22 106-5 



103-8 



103 



94 



44-40 



7-30 



22 106-5 



103-7 



103 



94 



52-35 



7-55 



22 106-5 



? 



103 



94 



0-05 



7-30 



Soap and Water. 







IV. 



Barom. 



30- S 



21-5 106-5 



103-5 



103-1 



92 



9 52-20 



6-10 



21-5 106-5 



103-7 



103-1 



91 



58-15 



5-55 



21-5 106-5 



103-5 



103-1 



91 



10 4-25 . 



6-10 



2L5 1065 



1035 



103-1 



91 



10-15 



5-50 



