National Geographic : 1936 Feb
Photograph byW.Robert Moore CAMEL TRAINS STOP TO TAKE ON WATER They have just delivered loads of fuel in Peiping, and now halt at a village watering trough on their way tothe coal deposits oftheWestern Hills, about ten miles from the metropolis. Marco Polo wrote of "a sort of black stone, which they (the Chinese) dig out of themountains, where itruns inveins. When lighted, it burns like charcoal, and retains the fire much better than wood; insomuch that it may be preserved during thenight." Onhisdeathbed friends urged the explorer, for the peace of his soul, to retract such incredible tales.