5o8 THE POPULAR SCIENCE MONTHLY. 



Secondly, when the deposits are compared, we find, as just stated, 

 that the chimney-like form is most prominent in the Yellowstone re- 

 gion, while New Zealand, in that respect also, is intermediate between 

 the park and Iceland. This more chimney-like form in the Yellow- 

 stone geysers has been explained by the statement that they contain 

 more silica in solution, but, as already stated in the analysis already 

 made, the percentage is usually smaller ; the one exception is in a 

 spring containing 53*76 grains of silica to the gallon of water, and it 

 is a spring that has no conical mound. It has also been suggested 

 that the dry air of our region may have some effect in this direc- 

 tion. We have no data at hand on this point ; but the simpler and, 

 to our mind, more reasonable cause is the greater age of our Ameri- 

 can region. Many of our geysers are secondary in their origin. 

 Thus Old Faithful is a geyser that has broken out on the summit 

 of a mound that had gradually closed up and become extinct. We 

 can not compare the actual thicknesses of the sediments or deposi- 

 tions of the three regions, and, even if we could, the comparison 

 would be apt to mislead us, as the rate of deposition in each region 

 and among individual springs must be variable. A great antiquity, 

 however, can certainly be accorded to all three of them. I will con- 

 clude these comparisons with a table of their elevations, including 

 with them some of the other localities mentioned in this article : 



Elevation in feet above 

 sea-level. 



Savu Savu, in Feejee Islands 9 



Hankadal geysers in Iceland 400 



New Zealand geysers 1,000 to 1,300 



Boiling Lake of Dominica, West Indies 2,400 



Geysers of Yellowstone National Park 6,000 to 8,000 



Geyser-region of Thibet 15,000 to 16,000 



EEPAKATION TO IIOrOCENT CONYICTS. 



By Dr. HEINEICH JAQUES, 



OP THB AUBTEIAN OHAHBEB OF DEPUTIES. 



LEGISLATIVE problems are, like books, subject to vicissitudes. 

 Solutions of the particular questions involved in single cases 

 may seem adequate to satisfy deeply-felt wants of the public ; yet 

 it may happen that the attention of the latter is — to the scorn of 

 the previous scientific work of years — first suddenly called to the 

 problems by some unexpected, exciting event. It may equally well 

 happen that a single sensational event may bring into current discus- 

 sion some legislative question hitherto wholly unconsidered by science. 

 The interest of all students is then turned for a short time to this 

 point ; its discussion occupies the saloons, fills the columns of the jour- 



