The Mentor: The Story of Coal, vol. 6, Num. 6, Serial No. 154, May 1, 1918

Shops may not run except at his behest, At forge and blast his strength is manifest. The rolls that rumble and the shears that scream And all the million miracles of steam

Of the many methods that have been devised for testing the air of mines for noxious gases none is more interesting than the use of caged canaries. These birds are much more susc...

Why do we need so much heat? Many of the peoples of the earth get along comfortably with much less heat than we consider necessary. Europeans and South Americans call us a “stea...