THE activity of the United States Coast and Geodetic Survey Department in carrying out a magnetic survey of the States and outlying territories has long been a subject of interest to magneticians, and ...

One of the most remarkable and mysterious technical advances in the history of the world is written on the hide of a 13th-century calf. Inked into the vellum is a chart of the Mediterranean so ...

THE latest American publication of similar scope referred to 1905, but declination charts for 1910 have been published. The observing stations used for the present charts exceeded in number those used ...