Cause of the Earth's Heat 



of the particles are caught by the outer 

 walls of the atom and their energy of 

 motion converted into heat. " The ra- 

 dium, in consequence, is heated by its 

 self-bombardment. ' ' 



The emanations of radium and of 

 other radioactive substances are present 

 everywhere in the atmosphere. Every 

 falling raindrop and snowflake carries 

 some of this radioactive matter to the 

 earth, while every leaf and blade of 

 grass is covered with an invisible film 

 of this radioactive material. These em- 

 anations are not produced in the air 

 itself, but are exhaled from the earth's 

 crust, which is impregnated with radio- 

 active matter. 



The question, then, arises, Is the 

 amount of radioactive matter present 

 in the earth sufficient to heat it to an 

 appreciable extent ? Prof. Rutherford 

 believes that it is. The present loss of 

 heat from the earth is equivalent, he 

 says, to that supplied by the presence 

 of about 270,000 tons of radium, which, 

 if distributed uniformly throughout the 

 earth's crust, corresponds to only five 

 parts in one hundred million million per 

 unit mass. The radioactivity observed 

 in soils corresponds to the presence of 

 about this proportion of radium. 



According to Prof. Rutherford's view, 

 the present internal heat of the earth 



tends to be maintained by the constant 

 evolution of heat by the radioactive 

 matter contained in it. The calcula- 

 tions of the age of the earth made by 

 Lord Kelvin, which were based on the 

 theory that the earth was a simple cool- 

 ing body, in which there was no further 

 generation of heat, cannot, then, apply, 

 for the present temperature gradient 

 of the earth may have been nearly the 

 same for a long interval of time. 



The new knowledge which the dis- 

 covery of radium and of its properties 

 has given inclines the author to the 

 theory that there is available in the sun 

 a vast store of atomic energy. ' ' If or- 

 dinary matter in breaking up emits as 

 much heat as radium, then it can be 

 deduced that the duration of the sun's 

 heat would be prolonged for about one 

 hundred times the estimate founded on 

 the condensation theory. ... If 

 this heat of atomic disintegration is 

 available, it would suffice to keep up 

 the present output of energy from the 

 sun for about five thousand million 

 years, a period of time which probably 

 both geologists and biologists would 

 consider sufficient for the processes of 

 organic evolution, while the duration 

 of the sun's heat in the future may pos- 

 sibly be extended for a hundred times 

 the estimate made by Kelvin." 



GEOGRAPHIC NOTES 



MAPS RECENTLY ISSUED BY THE 

 GEOLOGICAL SURVEY 



THE Batavia quadrangle, situated 

 in western New York, in Genesee 

 and Wyoming counties. It embraces 

 an area of about 220 square miles. In 

 addition to Batavia, a town of about 

 10,000 inhabitants, the smaller villages 

 of Bethany, Pavilion, Wyoming, Dale, 

 Linden, Lagrange, and Warsaw are 

 shown on the map. 



The Greene quadrangle of New York, 



including a portion of Chenango, Broome , 

 and Cortland Counties. The area rep- 

 resented includes the thriving village 

 of Greene, in Greenetown ; portions 

 of the towns of Smithville, German, 

 and McDonough, in Chenango County; 

 the village of Whitney Point, in the 

 town of Triangle ; portions of the 

 towns of Barker, Nanticoke, and Lisle, 

 in Broome County ; the town of Wil- 

 let and portions of the towns of Cin- 

 cinnati^, Freetown, and Marathon, in 



