  Electricity in the atmosphere provides an ideal topic for educational
outreach in environmental science. To support this objective, a simple
instrument to measure real atmospheric electrical parameters has been developed
and its performance evaluated. This project compliments educational activities
undertaken by the Coupling of Atmospheric Layers (CAL) European research
collaboration. The new instrument is inexpensive to construct and simple to
operate, readily allowing it to be used in schools as well as at the
undergraduate University level. It is suited to students at a variety of
different educational levels, as the results can be analysed with different
levels of sophistication. Students can make measurements of the fair weather
electric field and current density, thereby gaining an understanding of the
electrical nature of the atmosphere. This work was stimulated by the centenary
of the 1906 paper in which C.T.R. Wilson described a new apparatus to measure
the electric field and conduction current density. Measurements using
instruments based on the same principles continued regularly in the UK until
1979. The instrument proposed is based on the same physical principles as
C.T.R. Wilson's 1906 instrument. The constructional details of the instrument
are provided here.
