Headden — Group of Radium-hearing Springs. 305 



aluminic sulphate treated in this manner will liberate hydro- 

 gen, but not nearly so rapidly as this solution. A comparative 

 test showed the evolution of hydrogen from a solution of 

 aluminic sulphate to be less than one fifth as rapid. This 

 deposit placed in contact with cotton cloth or paper destroys it. 



The analysis of this sample presented some difficulties 

 and the footing of the analysis is over one hundred. The 

 sample was dried for three days at the temperature of the 

 room ; its weight was nearly constant during the last day. 



The analytical results were as follows : 



Per cent. 

 Loss on drying in water oven for ten hours __ 29*61 

 Loss on drying in air-bath at 147 c for two hours 15*35 



Insoluble in water 2'72 



S0 3 . 32-89 



Fe 2 3 __ 1-16 



FeO ._ Trace 



A1 2 3 -.. 6-71 



CaO _ 0-69 



MgO 3-33 



Na 2 4-68 



K 2 0-32 



Li 2 , Heavy trace 



Ignition with addition of lead oxide 4-45 



101-91 



The reactions of this material are those of an alum, and the 

 composition is between that of mendozite and pickeringite. 

 The material did not seem to me to justify a repetition of the 

 analysis, especially as I intended to visit the locality again to 

 determine, if possible, whether there is a spring at this point 

 whose waters would account for the formation of such a 

 deposit as this. On my next visit I found that heavy rains 

 following periods of freezing and thawing had caused large 

 quantities of material to come down from the cliff above, and 

 the point where I had obtained this sample was covered 

 deeply under mud and rocks. We succeeded in digging two 

 holes from which we obtained samples of water : one of them 

 was clear but the other was turbid, due to the presence of a 

 white precipitate. Neither of these samples was satisfactory, 

 but I could not obtain better ones. The following analysis 

 serves thoroughly well to show the character of the water 

 collected, though it is not so complete as some of the others. 

 The sample was not from a definitely located spring, and the 

 analysis given is of as much value as a fuller one would be. 



