in the Twenty Years before 1895 31 



clay obtained a few days later, certain black nodules were 

 found. These had no apparent connection with either plants 

 or animals, and I considered that my department had to 

 render an account of them. At the same time, I took them 

 to the laboratory with the expectation of finding that their 

 black colour was due to carbon. A portion heated before the 

 blowpipe did not change colour, but in the closed tube it gave 

 off a large quantity of water, which had a strong alkaline 

 reaction and an empyreumatic odour. The sample was then 

 submitted to the ordinary process of mineral analysis, and it 

 was found to be an ochreous nodule, consisting of the hydrated 

 higher oxides of manganese and iron, with traces of copper, 

 nickel, and cobalt, and varying amounts of the clay in which 

 it had apparently taken its rise. The physical structure of 

 the nodules reminded me at once of the stony masses to which 

 the black coral of February 15 was attached. They were 



:iined in the same way, and were found to be identical 



ructure and composition. 



In these few days, at the beginning of the voyage, the 

 carbonate of lime had been observed to disappear gradually 

 and completely, giving place to an apparently perfectly 

 amorphous and non-organic deposit. This deposit had the 

 character of a clay, with much ochre, both ferric and manganic, 

 diffused through it, and locally concentrated into nodules. 

 Proceeding westwards, the water became shallower again, 

 and on March 4 a sounding was obtained in 1900 fathoms. 

 As the depth became less the quantity of carbonate of lime 

 became greater, and the mud from this station was a globigerina 

 ooze containing 75 per cent, carbonate of lime. Going further 

 west, the water deepened again to over 3000 fathoms before 



loaled on nearing the West Indies, and here again the same 



ition of the nature of the bottom with the depth of the 

 water was observed. On this line the dredge was used almost 

 exclusively, and it acted well, generally bringing up a full 

 load of whatever mud was at the bottom. This afforded 

 precious opportunities of verifying the temperature slmwn 

 by the deep-sea thermometers used in the sounding. The 

 mass of mud was so great that it preserved inside an almost 



