232 Mr. Eve and Dr. Mcintosh on the Radium 



not then known. The results obtained, expressed in grams 

 of radium per gram of rock examined, are as follows : — 



Igneous Rocks. 



Granite Rhodesia 4*78 X 10- 12 



„ Cornwall 4*67 



Zircon Syenite Norway 4'6o 



Granite Cornwall 4*21 



„ Cape of Good Hope .... 3'57 



„ Cornwall 3"45 



„ Westmoreland 3'31 



Syenite Norway 2'44 



Granite Devon 1-84 



Blue ground Kimberley 1-68 



Leucite basanite Vesuvius 1*66 



Hornblende granite .... Egypt 1*22 



Pitchstone Isle of Eigg 1-03 



Hornblende diorite .... Heidelberg -99 



Augite syenite Norway *93 



Peridotite Isle of Hum '68 



Olivine euchrite „ „ -64 



Olivine basalt Skye -66 



Basalt Victoria Falls -63 



Hornblende granite .... Leicestershire "62 



Dolerite Isle of Canna *62 



Greenstone Cornwall '57 



Basalt Antrim *52 



Serpentine Cornwall -50 



Granite Isle of Rum *36 



Olivine rock „ „ *33 



Dunite , . . Loch Scaivig - 33 



Basalt Greenland *30 



Sedimentary Rocks. 



Oolite Bath 2-92x10-12 



„ St. Alban's Head 2-02 „ 



Marble East Lothian 1*93 „ 



Kimmeridge clay Ely 1*88 „ 



Oil-bearing sandstone . . Galicia 1*52 „ 



Roofing slate Wales ? 1-28 „ 



Gritty slate . . . Cornwall 1*25 „ 



Gault clay Cambridge 1*01 „ 



Clay Essex -86 „ 



Red sandstone East Lothian "84 „ 



Fine gravel Essex *71 „ 



Red chalk Hunstanton "53 „ 



Flint Essex "53 „ 



White marble India '27 „ 



Marble East Lothian -26 „ 



Chalk ; bottom of pit .... Cambridge -39 ,. 



„ top of same pit . . „ '12 „ 



These results show that the amount of radium in the 

 rocks near the earth's surface is greatly in excess of that 



required to maintain the earth at its present temperature. 



