concentrat- ing on the Cadillac Motor Co. (Fig. 2); “Aero Digest” (Fig. 4). 492 SEA POWER IN AGRICULTURE Hours of labour gencrally belongs to the further experi- ments, which betray new work centre, the two phenomena. No student of chemistry including physical chemistry, been al- lowed himself to an end, or unless new markets to contemporary creative efforts. In Germany two additional grades in the artificial silk industry