Open AccessOn a new analytical expression for the representation of the components of the diurnal variation of terrestrial magnetism
Publication year - 1913
Publication title -
proceedings of the royal society of london. series a, containing papers of a mathematical and physical character
Language(s) - English
Resource type - Journals
eISSN - 2053-9150
pISSN - 0950-1207
DOI - 10.1098/rspa.1913.0019
Subject(s) - character (mathematics) , expression (computer science) , clearance , declination , magnetic declination , variation (astronomy) , representation (politics) , set (abstract data type) , harmonic , limit (mathematics) , simple (philosophy) , mathematics , element (criminal law) , geophysics , earth's magnetic field , meteorology , geology , computer science , geography , mathematical analysis , physics , geometry , epistemology , magnetic field , law , astrophysics , philosophy , quantum mechanics , political science , programming language , medicine , politics , urology
In an enquiry as to the cause or causes that contribute to daily or seasonal change of a periodic character in any observational quantity, the primary step is the determination of a simple and comprehensive expression for the dominant features of the phenomenon. The periodic character of the variations of an element of terrestrial magnetic effect, such as declination, horizontal force, or the equivalent geographical components of force, is evident on almost every daily record obtained. When the hourly values are set out and properly cleared from non-periodic change (a problem of considerable subtlety), the historic method is to compute the Courier harmonic components. Another method that appears to possess great power is that so successfully carried out by Dr. W. N. Shaw in representing the daily and seasonal changes of meteorological elements by means of " isopleths."