A summary of the results of the recent magnetic survey of Great Britain and Ireland conducted by professors Rücker and Thorpe: Part II. On the accuracy of the determination of the local disturbing magnetic forces

It need hardly be said that the main object of so elaborate a Survey as that we have carried out was not so much to define the precise positions of the terrestrial isomagnetics, though this was essential to our purpose, as to study local magnetic disturbances. The method we adopted for determining the Disturbing Forces at any given place was the simplest and most obvious, but, as far as we are aware, it had not previously been used in working up surveys of districts as large as the United Kingdom. The magnetic elements given by direct observation were the Declination, Horizontal Force, and Dip. From, these the northerly, westerly, and vertical components of the magnetic force were determined.