This is prettier (and much more helpful) version of the above link to the Challenger reports. It contains all the woodcut illustrations from the various reports as well as the links to the reports themselves.
http://19thcenturyscience.org/HMSC/HMSC-INDEX/index-illustrated.htm
The way I came across that website is a bit interesting in itself.
Looking at ancient maps relating to the discovery of Australia led me to think about early navigation which led me to the ‘lead line’.
“The lead line is for measuring the depth of water. Like all good inventions it has the grace of simplicity. The lead weight, usually weighing 7 pounds for a 25-fathom line and 14 pounds for a 100-fathom line, is cup-shaped at its base. This hollow is filled with tallow (known as arming the lead) so that when the lead strikes bottom, particles of the seabed stick to the tallow: sand, mud, stones, shells, etc.”
This made me wonder if this would be an interesting science project for me or someone on the forum. Hire a boat and map the local sea bed. Nylon fishing line is available up to and perhaps beyond 1 km in length. Some modern glues might be better than tallow.
So I went looking for old maps that showed the seabed composition. One for Nantucket shows entries including “dine dark grey sand, black specks, stones, broken shells” as “fne.dk.gy.S.bk,Sp,St,brk,Sh”. I was beginning to despair of finding a map of Australia showing seabed composition until I ran across the following map from 1884 (1924 edition):
http://digital.slv.vic.gov.au/view/action/singleViewer.do?dvs=1367793122079~29
At first sight this appears to be just a map of the southern half of Australia, but look closer and it shows water depths down to 3100 fathoms (5.7 km). Even more, it shows seabed composition at that depth. A companion map of northern Australia and New Guinea from 1934 shows water depth and seabed composition down to 4300 fathoms (7.8 km). The index on the 1884 map includes pt. for pteropod and gl. for globigerina. Pteropods are swimming snails and globigerina are globe-shaped foraminifera.
That got me interested in who was investigating the sea bed down to 3100 fathoms prior to 1884. The Challenger expedition of 1873-76 was. It turns out that only one point south of mainland Australia on the 1884 map comes from the Challenger expedition, at sample site 160, west of Tasmania and south of Ayre Peninsula. Even that point is specially interesting in that they found manganese nodules there.
Am now about to follow up the report “ANALYTICAL EXAMINATION OF MANGANESE NODULES, with special reference to the PRESENCE or ABSENCE of the RARER ELEMENTS. By John Gibson, Ph.D., F.R.S.E.”. http://19thcenturyscience.org/HMSC/HMSC-Reports/1891-DeepSeaDeposits/htm/doc.html
Was very surprised to learn that the detailed chemical analysis of deep ocean manganese nodules had been done by 1891, I’d thought it was a recent finding.