Abstract
A quick, versatile and moderately sensitive instrument for measuring the effects of time, temperature and direct or alternating magnetic field on the remanent magnetization of rocks has been constructed. The instrument combines in one unit a ballistic magnetometer, a furnace, a solenoid and nulling coils. The ability to operate the solenoid at any sample temperature on ac as well as dc is a new feature; in addition the capabilities of the other components are significantly improved over previous instruments of the same type. The magnetometer, incorporating a galvanometer amplifier, reliably measures magnetizations of 10-5 e.m.u. per cm3 or larger. Experiments which can be performed without removing a sample from the instrument include: production and measurement of isothermal, viscous, anhysteretic and thermoremanent magnetizations; continuous thermal demagnetization without intermediate coolings; alternating field demagnetization and hysteresis measurements at ordinary or high temperatures.