APPENDIX A
FURTHER DETAILS ON THE METHODS USED BY ADAMS IN 1933 FOR "CRYSTAL INTERCONNECTION"

Two different methods of interconnection between the two crystals were employed -

1. By copper wire from a crystal mounted in a crystal cup, the other end of which is connected to the crystal set proper.
2. By direct physical contact (under small pressure) in an assembly of two crystal cup holders with vertical mounting brackets secured to a small insulated base board.

Connections to this small module of two crystals was achieved with the use of the then available vertical cantilever type cats whisker holders, providing stable connections to the central junction and input and output points. The words 'emitter', 'base', 'collector' hadn't yet been born for this new device, which, of course, was destined to become known today as a "transistor".

There appeared to be no difference in the performance between these two methods of connections. As a matter of interest, I quote here from C. Tissot (Outline of Wireless by Ralph Stranger) "Tissot's tests established that; the form of contact is of little importance. Even large polished plates placed between two metallic electrodes make sensitive detectors! The use of a battery in series with the detector, with proper value and direction of the battery e.m.f., increases sensitiveness."

The following is the method devised to ensure crystal amplifier electrical contact rigidity. On completion of the construction of the crystal amplifier, two major problems had to be addressed, i.e., those of the three electrical crystal contacts' stability, permanence and reliability. The second problem being that of attack from varying ambient air conditions, such as the onset of high humidity forming troublesome chemical changes and consequent coating on the crystal's surface - thereby increasing the electrical resistance of the three amplifier contact points. This then disturbs efficient operation or, at worst, causes the crystal point/s to cease conducting completely. I conceived a method by which to overcome these two problems with the aid of an excellent sealant, i.e., that of utilising New Zealand Kauri tree gum (resin). By melting the gum and applying it by drip feed at the points, this avoided disturbance of the highly sensitive contacts of the needles on the crystals' surface.