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.
Photo Category: Oceanography - Historical instruments