Popular Srirncr MoiifhJi/ 



687 



Steaming Frozen Ground 

 for Gold 



0\'\-.R much of nortliern 

 Alaska and British Co- 

 lumbia the ground is forever 

 solidly frozen for man\- feet 

 beneath the surface. DuriiiL; 

 the warm summer mouths, 

 w liere the o\erl\ing mos> 

 has been removed, the soil 

 may thaw out for a few 

 inches or feet, permitting 

 placer mining to be carried 

 on by hydraulic mining 

 methods. For the most part 

 this natural thawing is far 

 too slow to prove practic- 

 able in a region where the 

 working season is only a few 

 months in the year. The 

 ingenuity of man, therefore, 

 has devised a method to 

 assist Nature in her work. 

 Long, hollow ttibes, called 

 "steam points," tapered at 

 one end and enlarged at the other 

 to withstand repeated blows and 

 carrying a connection to a stt 

 line, are driven in rows across 

 the face of the grou 

 Steam under pressure i 

 forced through these 

 pipes for several 

 hours until the sec- 

 tion is thoroughly 

 thawed. Then 

 the points are 



n e a t h t h e 

 ground in 

 drifts, during 

 the winter 

 months, the 

 gravel removed 

 being piled in 

 great dumps 

 to await the 

 summer season 

 of abundant 

 flowing water. 



The 

 and 



Long, hollow tubes are driven into the ground in rows 

 and steam is forced through them for several hours 



Look Out! Perhaps the Man You're 

 Talking to Wears a Detectaphone 

 .ATENT has been issued 

 :o William Heymann, of 

 I'ashington, D. C, on a 

 device which records on 

 a graphophone drum 

 hispered conversa- 

 tions, without the 

 speaker being 

 aware of the fact. 

 The receiver, 

 which is of the 

 usual detecta- 

 phone t\pe, is to 

 l)e worn beneath 

 the shirtfront, 

 and the electric 

 batter\- and cyl- 

 inder of the re- 

 cording grapho- 

 phone are to be 

 hooked to the 

 wearer's belt. 

 Release a 

 wound-up dock- 

 spring ami the 

 needle of the 

 graphophone 

 traces the zig- 

 receiver is worn beneath the shirtfront zags produced by 



the graphophone is hooked on the belt the SOUnd waves. 



