By FRED. HOFFMANN.
ON the first day of August, 1874, the chemists of Great Britain dedicated a monument to the British discoverer of oxygen. On the same day a large number of American chemists assembled at the beautifully located village of Northumberland at the junction of the two branches of the Susquehanna River, in order also to pay homage to the memory of that remarkable theologian, philosopher, and naturalist, Joseph Priestley, who lived and died in that quiet Pennsylvanian village. In the orations delivered at this occasion of the centennial of the discovery of oxygen, the element which for the following half century became the cornerstone for the structure of a new chemical philosophy, equal justice was done, especially by the late Prof. Sterry Hunt and Prof. Lawrence Smith, to both discoverers of oxygen, Priestley and Scheele. Both men, though of different caliber and station in life and searching in different directions, recognized almost at the same time and independently of each other the nature of oxygen, and to a large extent also the important part which this element plays in the commonest chemical processes and changes of matter. Yet both, skilled and ingenious experimentalists though they were, and Scheele keen and discerning in deduction and application, prepossessed by the doctrine of Stahl, then prevalent and apparently settled, missed the real bearing and ultimate consequence of their discovery, and died defenders of the theory of phlogiston—the very men who furnished the facts and the weapons with which that hypothesis was shattered a few years afterward by Lavoisier, and a new system of chemical philosphy was established.
The memory of these three contemporary representative investigators of the three foremost nations of their time—England, Germany (Scheele was a German by nationality, born in Pomerania, then under Swedish rule), and France—has ever since been honored. Monuments have been erected to Lavoisier in Paris, to Priestley in Birmingham (1874), and to Scheele in Köping (1827). Scheele especially has repeatedly been remembered by his grateful adoptive country, Sweden. In 1790, four years after his death, the Academy of Sciences in Stockholm, of which he had been a member, had a medal struck to his memory. It contained on one side his portrait in relief, and on the other a symbolic representation of the discovery of oxygen, and the inscription, "Ingenio stat sine morte decus" (the beauty of his genius stands immortal). In 1827 the Academy had a second medal struck, with Scheele's portrait, and on the other side the veiled