[Phys-l] Need advice to built earth resistivity meter

["Roberto Carabajal" <rcarabaj@copelnet.com.ar>]

> Hello Friends:
>
> One studient have the idea of built an earth resistivity meter capable of
> sounding very deeply, for example, used to detect water at 1500 feets. The
> problem involves metering of very low current values with good  accuracy,
> and good knowledge of earth current distribution density laws. 
> It is an interesting problem but we need help finding circuits that can be
> used in this project,  especially because the idea is to use standard
> commercial equipment (low  cost digital meters and common batterys).
> Perhaps somebody have seen such experimental equipment. Any help would be
> appreciated. 
>
> My best regards.
> Roberto