192 



ing strain ; and the rapidity of descent has hardly if ever been 

 equalled in speed by smaller lines when weighted nearly up to their 

 breaking strain, as shown in the American soundings. One hour 

 from the time we let go, the intervals showed that the weight was 

 down. 



I ran the easting down between the parallels of 35 and 38 S., 

 from the Cape of Good Hope eastward outside Mauritius in the 

 Indian Ocean, in the route of many doubtful dangers, and on near- 

 ing them the lead was brought into play. The first was the ' Bruns- 

 wick,' on which is marked 85 fathoms, deep enough certainly for any 

 ship that swims ; but to clear up all doubt, two casts were obtained not 

 far from its position, of 1410 and 1102 fathoms, without reaching 

 bottom. Then comes the ' Atalanta,' having three positions, one on 

 our Admiralty Charts, and two from Horsburgh, giving it as an ex- 

 tensive shoal under water, with pointed rocks on its western part. I 

 passed from the westward between the northern position, and the 

 first in order to the southward, and got four deep casts, besides 

 several of 50 and 80 fathoms. The first was 1110 fathoms down by 

 intervals, but no valve coming in, it appearing to have been broken 

 off from the rod by striking some hard substance, either at the 

 bottom or on its passage up or down, I immediately determined on 

 getting another cast, although darkness was coming on. The 

 weather fortunately was calm with very little sea on ; so stationing 

 a number of lanterns, the lead was at once dropped over the bows, 

 and as satisfactory a cast was got as could possibly be wished, the 

 sinker striking bottom by intervals at 1 1 20 fathoms, thus proving 

 the correctness of the first sounding, and finally, the valve coming in 

 with a sufficient portion of bottom to prove it again. This specimen 

 consisted of what appeared to the eye very fine sand covering a hard 

 substance (coral I suspect), but under the microscope it was found 

 to be some of the most beautiful specimens of Diatomacese that can 

 be imagined. I send home these specimens, small as the quantity 

 is, being quite sufficient for examination. The next morning further 

 to N.E. with 800 fathoms, no bottom: another cast still further 

 N.E., bottom with 900 fathoms, bringing up another specimen of 

 the same sort of sand as last night, with a small pebble amongst it. 

 [Capt. Pullen here explains how his attention was drawn to parts 

 of the sea where the surface was covered, for a considerable space, with 



