in the Twenty Years before 1895 59 



accompanied by the homologous oxides of nickel and cobalt. 

 The association of these four metals and the constancy of 

 character observed in the nodules, suggested to me as a first 

 idea that they were perhaps simply the products of the oxidation 

 of meteorites. Further acquaintance with them rendered this 

 explanation very improbable. A characteristic feature of the 

 nodules is that when heated in the closed tube they emit a 

 -tnmgly empyreumatic odour and give off steam which con- 

 denses to an alkaline liquid 1 . As my attention was thus early 

 ted to the formation of ochres, I carefully studied every 



irrencc of them. The organic matter revealed by heating 

 in the closed tube was as invariably present as the ochres, 

 and in the many instances, principally in the Pacific, where 

 large fragments of pumice were brought up from great depths, 

 these masses were perforated by annelids and the holes produced 

 were almost always clothed with a black ochreous lining of 

 the same composition as these manganese nodules, and the 

 pumice in the neighbourhood of the holes was stained of blackish 

 brown colour from the same cause. 



This frequent occurrence of the ochreous formation in 

 connection with the deep sea annelids and the invariable 

 occurrence of organic matter in freshly collected nod' 

 suggested the connection of the formation of the ochreous 

 deposits with the organic life on the bottom. Ochres, especially 

 hydrated ferric oxide, are essential constituents of the oceanic 

 "red clay." When the sounding tube brings up a sample 

 of bottom from one of these regions, it is quite usual to find 

 that the upper layers of the samples are of a red colon i , \ 



mud immediately below is of a bluish-black colour. As 



dredge furnished evidences of the abundance of life in the 

 mud, as the difference of colour of the upper and 1<>\\< T 1 

 of the mud was evidently din- to a ditlnvnt state of oxid.r 



iron in it, and as the water in contact with the surface 



of tin- mnd always showed a deficiency of oxygen, there was 



difficulty in concluding that the existence of animal 



in the mnd had some effect in modifying i< .d 



composition. 



1 I IK \ lotef "-served in the .m. 



