At this time we formed an acquaintance with Dr. Wollaston, which soon became a lasting friendship. He was gentlemanly, a cheerful companion, and a philosopher; he was also of agreeable appearance, having a remarkably fine, intellectual head. He was essentially a chemist, and discovered palladium; but there were few branches of science with which he was not more or less acquainted. He made experiments to discover imponderable matter; I believe, with regard to the ethereal medium. Mr. Brand, of the Royal Institution, enraged him by sending so strong a current of electricity through a machine he had made to prove electro-magnetic rotation, as to destroy it. His characteristic was extreme accuracy, which particularly fitted him for giving that precision to the science of crystallography which it had not hitherto attained. By the invention of the goniometer which bears his name, he was enabled to measure the angle formed by the faces of a crystal by means of the reflected images of bright objects seen in them. We bought a goniometer, and Dr. Wollaston, who often dined with us, taught Somerville and me how to use it, by measuring the angles of many of our crystals during the evening. I learnt a great deal on a variety of subjects besides crystallography from Dr. Wollaston, who, at his death, left me a collection of models of the forms of all the natural crystals then known. Though still occasionally occupied with the mineral productions of the earth, I became far more interested in the formation of the earth itself. Geologists had excited public attention, and had shocked the clergy and the more scrupulous of the laity by proving beyond a doubt that the formation of the globe extended through enormous periods of time. The contest was even more keen then than it is at the present time about the various races of prehistoric men. It lasted very long, too; for after I had published my work on Physical Geography, I was preached against by name in York Cathedral. Our friend, Dr. Buckland, committed himself by taking the clerical view in his "Bridgewater Treatise;" but facts are such stubborn things that he was obliged to join the geologists at last. He and Mrs. Buckland invited Somerville and me to spend a week with them in Christchurch College, Oxford. Mr. and Mrs. Murchison were their guests at the same time. Mr. Murchison (now Sir Roderick) was then rising rapidly to the pre-eminence he now holds as a geologist. We spent every day in seeing some of the numerous objects of interest in that celebrated university, venerable for its antiquity, historical records, and noble architecture.