Experiments in Underground Communication Through Earth Strata

Author:	Ilsley, L. C.
Additional Authors:	Freeman, H. B.
Year:	1928
Document Type:	N/A
SUDOC:	C 22.5:433
Series:	United States Bureau of Mines Reports
Report Number:	Technical Paper 433
Subjects:	Mine rescue work.
	Coal mines and mining.
	Signals and signaling.
Link:	http://digital.library.unt.edu/ark:/67531/metadc66438/