iii Aucltlniitl H:ii*lmur, ; L i i d it Itas Itc*cit often used in D i s c o w q investigatioiis. lklonc$\cr, it w t ~ i i h to linvc fallen into disuse now, as some
workers foutitl it iinatdisfactory. 1)r. H. F. 2'. Herdman of the National
Iiistitute of 0ccaiiogmph.v itifot~nis r t w that he has used it with success
Fia. 5. Bow-framed or " Amphioxus " dredge, as umd at Plymouth. If the trawl
gallows are illsufficiently high to swing thr dredge inboard it may be necessary
to hoist i l l by separate tackle. (Z'hoto: U. $1. Grigg.)
for obtaining sediment samples, csj"ial1y of red clay, in deep water,
but if worked like an ordititiry dredgc it is uilsatisfactorj. It needs
first to be lowered to thc bottom, with a considerable length of heavy
chain (100 m) immediatrly i i i front of it. When on the bottom, slow
towing is commenced, and n good sample is obtained. It therefore