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Rh per cent. of its own weight, and, if we adopt, for the normal product to inject, $4/5$ of tannic acid and $1/5$ of tannate of protoxide of iron, the cost would amount to from $5/100$ to $6/100$ of a franc, making, in all, an expense of $66/100$ of a franc per sleeper.

Trials of this process are at this moment in course of execution upon a grand scale, by the Railway Company of the East, and the Administration of the National Telegraphs, with the authority and coöperation of the Minister of the Interior.—Comptes Rendus.



ERMANY assembled in 1869 her greatest savants to celebrate the centenary anniversary of the birth of Alexander von Humboldt, her greatest dead. The highest honor of this occasion was bestowed on Prof. Helmholtz, who delivered the opening oration. He reviewed the progress made in the natural sciences with special reference to the labors of German students, and said: "In Germany there has always been a greater fearlessness of the consequences resulting from speaking the whole truth than anywhere else. The eminent savants of England and France are still obliged to bow to the dictates of social and ecclesiastical prejudices, and, when they speak openly, they do it to the injury of their social standing. Germany is bolder; she confides in what has never proved false—that the whole truth is the best remedy for the evils of truth imperfectly stated."

The Academy of France lent new force to his statement by refusing to elect him a corresponding member, on account of the advanced ideas connected with his name. A French critic rebuked his country-men for hesitating to bestow on Helmholtz, the greatest living physicist of this century, so slight an honor, with the remark: "For his glory nothing is wanting; but he is wanting for ours." The Academy elected him in the following year.

was born August 31, 1821, in Potsdam, the Prussian Versailles, the town of palaces, which gave birth to Alexander von Humboldt, and holds the ashes of Frederick the Great. His father was a teacher at the gymnasium in Potsdam, and a man possessed of a great store of knowledge. Under his guidance Hermann was soon prepared to enter the institution, where, as usual, too much Latin and Greek was taught for his youthful taste. He was, however, not permitted to shirk any of his studies, and, with that patient perseverance which is a dominant trait in his character, he ran through the whole curriculum of the gymnasium before he had 