272 CARNEGIE INSTITUTION OF WASHINGTON. 



long been known to do. Further efforts have been made in the course of 

 these investigations to determine the most effective measures of activity of 

 magnetic, electric, and solar phenomena. (See pp. 289-292.) 



(4) Dynamic and tilting deviations. — This is partly a theoretical and partly 

 an experimental investigation conducted by Mr. Peters with the view of 

 ascertaining what appreciable errors may be introduced in magnetic measure- 

 ments at sea as the results of the effects of the ship's motions on magnetic 

 systems whose center of gravity may or may not fall in the axis of support. 

 Besides their bearing on our ocean work, the results of the investigation will 

 be of importance in the design of instruments and study of the best method 

 of observation of the magnetic forces in upper levels of the atmosphere. 

 (See p. 306.) 



(5) Publication work. — Good progress has been made with various papers 

 for Volume V, "Researches of the Department." 



experimental'^work in magnetism.^ 



(1) Magnetization by rotation. — The experiments have been conducted as 

 in previous years by Dr. Barnett, in the specially constructed Experiment 

 Building on the Department's site at Washington. A long-suspected error 

 in the 1917 experiments by the magnetometer method has been successfully 

 eliminated, so that the results derived from the two independent methods 

 (electromagnetic induction and magnetometer) are now in satisfactory agree- 

 ment (see p. 284). Dr. Barnett interprets his results to date as follows: 



"Rotating any ferromagnetic substance investigated at one revolution per 

 second is equivalent to placing it in an axial magnetic field with intensity 

 — 3.5 X 10"^ gauss, within about one part in ten. This result would be 

 expected if a single type of negative magneton, with ratio of angular momentum 

 to magnetic moment equal to m/e, one-half that of a ring of electrons, were 

 responsible for ferromagnetism. Abraham showed in 1903 that a superficially 

 charged Lorentz electron in rotation has the moment and the momentum 

 giving this ratio. If a ring of electrons is chiefly responsible for ferromagnet- 

 ism, positive magnetons also participate, as stated before." 



(2) Theories of magnetism. — As a member of the National Research Coun- 

 cil's Committee on Theories of Magnetism, Dr. Barnett prepared a paper on 

 "The Angular Momentum of the Elementary Magnet." (See abstract, p. 285.) 



(3) Electrodynamics of moving bodies. — Dr. Barnett has continued his 

 theoretical investigations under this head, and has contributed three papers 

 to the American Ph3^sical Society. (See abstract, p. 286.) 



(4) Sine galvanometer. — Remaining details were completed for the mono- 

 graph which has appeared in Volume IV, Researches of the Department, and 

 a paper was presented on the completed instrument at the Toronto meeting 

 of the American Physical Society, December 1921. 



EXPERIMENTAL WORK IN TERRESTRIAL ELECTRICITY.^ 



(1) Atmospheric-electric apparatus for observatories and special expeditions. — 

 On the basis of studies and experiments made, it was possible further to 

 standardize and perfect the instruments for atmospheric-electric observations 



» From the report of the chief of the section, S. J. Barnett. 

 ^ From the report of the chief of the section, S. J. Mauchly. 



