An introduction to the Dilmount apparatus .
In 1927 Elmo Dilmount had yet to achieve the fame that would follow him throughout his later life. It was in the early months of that year that he would construct the very first “ludiscope”, thus making magnetism universal!
The device consists of a small magnetic field generator coupled to a field probe with three dimensions of freedom. Between the field generator and the probe is a glass plate that serves as the neutral terminal of a primitive type of Mollot Cell known as a “Poulson Cup.” The reason that this is used rather than a more standard cell is so the rate at which the granules transmit can be directly observed.
To operate the device, the user simply clips a sample to the glass plate. Next, he positions the magnetic generator in such a way that its field passes through the edge of the sample. The tip of the probe is positioned at the very outside of the field’s influence and then slowly lowered into the field using the focus screw. As the operator is doing this, he carefully observes the granules in the Poulsen Cup for any corona discharge. This is accomplished with much greater ease if the operator is wearing polarized spectacles. When a discharge is observed, the distance from the probe to the sample is measured and the color and axis of the discharge are noted. Then all that is needed is to look up the figures in the Dilmount Mass Standards Handbook to obtain their numeric values. Thus by multiplying the Handbook’s Remizov number by the D/D (distance at discharge in millimeters) the magnetic value of the sample can be determined