Marine Muds and Nodules 153 



upper part of the bottle, left dry when some of the water 

 and precipitate had been poured out. This took place at 

 the time, and was to be expected. The two other bottles, 

 which were filled up with the manganous sulphide at the time 

 of preparation, have never been opened since, though they 

 h;i\v all the time been exposed to the light, and are exactly 

 in the condition in which they were when bottled nine and 

 a half years ago. There is no trace of oxidation. 



Manganous Sulphide and Hydrous Ferric Oxide. Both 

 substances are used, suspended in distilled water. If the 

 ferric oxide be cautiously added to the sulphide of manganese, 

 and both suspended in water, the red patches are seen to 

 disappear, and the general colour of the suspended matter 

 becomes rather lighter in colour than the MnS, and there is 

 no formation of FeS. If further additions of Fe 2 O 3 be made, 

 red flakes deposit themselves. They do not appear to be 

 unaltered Fe 2 O 3 , but are exactly like the "red cherty particle- 

 of manganese bottoms. On still further additions of Fe 2 O 3 , 

 the colour changes quickly, though not instantaneously, to 

 black, with, however, a large admixture of white particles, the 

 two being easily seen to be perfectly distinct. There is also 

 a quantity of precipitated sulphur which remains floating in 

 the liquid long after the heavy matter has subsided. 



Prosecuting this line of experiment, I made three mixtures 

 in suitable flasks. 



i . ontaine.l MnS and Fe 2 O 3 , the MnS being in excess. 

 re was formation of red cherty particles, but nothing black. 

 2. The same substances, but containing the Fe^Og 

 in excess; the mixture quickly turned black. 



No. 3. The same as No. 2, onlv it vras made up with 



it turned black alnm-t at 01 



These experiment- were repeated and with the same result-. 



.ibove flasks, Nos. I, 2, and 3, were corked up and allowed 



to stand over ni^ht. No. I contained numerous black particles, 



v ones, and an excess of MnS as well fti 



bur. Nos. 2 and 3 were much .1- the\- ha.l l>em the ni-ht 



re, except that the white particles had almost entireh 



as also all red particles. ions are 



bly accelerated by heat. 



