Figure 1. A drilled roller (round boulder) used as a sounding weight. Figure 2
. Ordinary sounding lead weight, sometimes attaining many kilograms. The lead
dates from the Christian era. The trapezoidal form with a recess for tallow and
acquiring bottom samples dates from a few centuries back. In this form, millio
ns of sounding were made. Fig. 3. French sounding lead used in many expeditions.