Page:Popular Science Monthly Volume 64.djvu/571

Rh of the presentation of a statue of Priestley to the town of Birmingham is printed in the issue for November, 1874. Priestley's own account of the discovery of oxygen was reprinted in the issue for December, 1900. To these articles those readers may be referred whose attention has been attracted to Priestley by the recent commemoration.

Priestley's discoveries were of epoch-making importance in the history of chemistry; his radical views in politics and theology anticipated in certain directions the course of subsequent thought, and his career is full of dramatic interest, especially to us in America, among whom he took refuge from persecutions at home. Yet it is not often that one of the twenty-five volumes containing Priestley's collected works is taken down from the shelves of the library. The vast range of his controversial writings belongs to the past, and his scientific work was in a sense an episode in his life and in the development of science. But the courage with which he defended what was then heterodoxy in religion and radicalism in political affairs deserves our admiration, and the discovery of oxygen will always remain a landmark in the progress of chemistry.

At the middle of the seventeenth century, chemistry had not yet found its Copernicus or Newton. From our point of view the confusion was extreme. Air, water and fire were regarded as elementary substances. It was supposed that when anything was burned or when an animal breathed, a substance called phlogiston passed into the air and vitiated it. So when Priestley discovered oxygen, he called it dephlogisticated air, it being, 'between five or six times as good as common air.' Priestley did other work of importance in connection with gases, but did not appreciate the real bearings of his own discoveries and can not be placed in the same rank with Cavendish and Laviosier. But he will always be remembered for one of the most important discoveries in the history of science.

appears that in Germany, as in England, the great men of the nineteenth century have scarcely bequeathed their genius to their successors. It is quite impossible for Berlin to fill the places vacant by the deaths of Helmholtz, Virchow and Mommsen. One man of that generation the university still has, and it does well to do him honor on his ninetieth birthday. Professor Zeller does not rank with the greatest of his contemporaries, but he represents the highest scholarship, the type which is in danger of submergence beneath the flood of executive work and business detail of modern life.

The work of Professor Zeller carries us a long way back. Starting from the then prevalent Hegelianism, he was one of the first to take a decided stand against the à priori construction of the world, and claim that we must go back to the epistemology of Kant and develop it in the light of modern science. But he is best known for his 'Philosophy of the Greeks,' the first volume of which was published sixty years ago. This work has continually been revised for subsequent editions; it was followed in 1872 by a history of German philosophy since Leibnitz and by numerous other publications, especially on the relation of philosophy to science and on the philosophy of religion.

lost only five years ago its eminent paleontologist. Professor O. C. Marsh, and now we are compelled to record the untimely death of his successor. Professor C. E. Beecher, which occurred on February 14, at the age of forty-eight years. Beecher was graduated from the University of Michigan in 1878, and for ten years was assistant to Professor James Hall in the New York Geological Survey. In 1888 he was called to Yale