The primitive magician was popularly supposed to know all that could be known and his powers were conceived to be unlimited. But in characterizing as modern magic the degree of control so far acquired over the ability of coal to serve the purposes of men we can claim no such omnipotence or omniscience. When using coal simply as a source of power best modern practice is able to utilize less than one-third of its available energy, and average practice probably not as much as one-fifth. Of its possible by-products only an insignificant fraction are yet being utilized, and it is comforting to reflect that since we have available, in this country, enough coal to last us at least a thousand years, and perhaps much longer, there is time to acquire the knowledge of how to use it more efficiently. And in justly being proud of the progress that has been made, let us couple it with a humble recognition of the possibility that our descendants may look back on what we have done with the same tolerance of our limitations that we display toward the technology of the seventeenth century. (page 24)