Date: 1874
For some years there had been a population of engineers engaged in the work on earth equal to that of London in the nineteenth century, but we now so increased the number as to equal the popula- tion of Britain at that period.  The machinery and plant Avere augmented in a like ratio.  New inventions meanwhile flowed in, AAirich Avere so numerous and so ingenious as to acclimatize the workers to the subterranean regions, and alloAV them to dip with greater speed and more ease into the earth's interior.