THE PROGRESS OF SCIENCE. 



567 



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 dra- 

 matic 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 col- 

 lected 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 cour- 

 age with which he defended what was 

 then heterodoxy in religion and radi- 

 calism in political affairs deserves our 

 admiration, and the discovery of oxy- 

 gen will always remain a landmark in 

 the progress of chemistry. 



At the middle of the seventeenth cen- 

 tury, chemistry had not yet found its 

 Copernicus or Newton. From our 

 point of view the confusion was ex- 

 treme. Air, water and fire were re- 

 garded 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, ' be- 

 tween 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 bear- 

 ings of his own discoveries and can not 

 be placed in the same rank with Caven- 

 dish and Laviosier. But he will always 

 be remembered for one of the most im- 



portant discoveries in the history of 

 science. 



PROFESSOR EDUARD ZELLER. 



It appears that in Germany, as in 

 England, the great men of the nine- 

 teenth century have scarcely bequeathed 

 their genius to their successors. It is 

 quite impossible for Berlin to fill the 

 places vacant by the deaths of Helm- 

 holtz, Virchow and Mommsen. One 

 man of that generation the university 

 still has, and it does well to do him 

 honor on his ninetieth birthday. Pro- 

 fessor 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 d priori construction of the 

 world, and claim that we must go back 

 to the epistemology of Kant and de- 

 velop it in the light of modern science. 

 But he is best known for his ' Phi- 

 losophy 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 Ger- 

 man philosophy since Leibnitz and by 

 numerous other publications, especially 

 on the relation of philosophy to science 

 and on the philosophy of religion. 



CHARLES EMERSON BEEGHER. 

 Yale Uniyeesity lost only five years 

 ago its eminent paleontologist. Pro- 

 fessor 0. 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 Univer- 

 sity of Michigan in 1878, and for ten 

 years was assistant to Professor James 

 Hall in the New York Geological Sur- 

 vey. In 1888 he was called to Yale Uni- 



