Henry Drummond (1851 - 1897) was a Scottish evangelist, writer and lecturer. In 1877 he became lecturer of natural science in the Free Church College. Drummond believed that the scientific principle of continuity extended from the physical world to the spiritual. He traveled to Africa and Australia and in 1893 delivered the Lowell Lectures at Boston. Drummond poses these question in his introduction," The real problem I have set myself may be stated in a sentence. Is there not reason to believe that many of the Laws of the Spiritual World, hitherto regarded as occupying an entirely separate province, are simply the Laws of the Natural World? Can we identify the Natural Laws, or any one of them, in the Spiritual sphere? That vague lines everywhere run through the Spiritual World is already beginning to be recognized. Is it possible to link them with those great lines running through the visible universe, which we call the Natural Laws, or are they fundamentally distinct? In a word, Is the Supernatural natural or unnatural?"