was born in Stirling, Scotland on August 17, 1851. As a young man he attended Edinburgh University where he particularly enjoyed the natural sciences. However, driven by a desire to preach the Gospel, he entered the Free Church of Scotland, where, before taking his own pastorate, he worked with D.L. Moody on his evangelistic efforts. In 1877 he became a teacher of natural science at the Free Church College. He spent six years lecturing and writing until, in 1883, he received an opportunity to conduct a geological survey in southern Africa. Upon his return a year later, he found himself to be rather famous in his homeland. Later on he would write of his work in Africa and participate in a similar work in Australia. He continued to write and lecture in England and the United States until his death on March 11, 1897.