1889.] of the various Species of Heavenly Bodies. 249 



Water (H 8 0) 9-51 



Silica (Si0 2 ) 19-34 



Lime (CaO) 3-19 



Alumina (A1 3 3 ) 6'36 



Ferric oxide (Fe 2 3 ) 2670 



Magnesia (MgO) 1-79 



Oxide of manganese (MnO) 26*46 



nickel (MO) 1-82 



Oxygen 6'31 



101-48 



The specimen examined was from Station 276, 2350 fathoms, South 

 Pacific. 



I have observed the spectra of some of the nodules, which were 

 kindly placed at my disposal by Mr. Murray. 



In the oxy-coal-gas flame, lines of Na, Tl, Li, K, Mn, and Fe are 

 seen. The brightness and persistence of the thallium line at 535 is 

 very remarkable, and is especially interesting since the line is seen in 

 the aurora and in one or two meteorites. The red line of lithium, 

 which is seen in many of the meteoric flames, is also bright in the 

 spectrum of the nodules. The manganese fluting at 558, the one 

 coincident with the chief line of the aurora, is also seen in the 

 spectrum of the nodules, but it is not nearly so bright as the thallium 

 line. The iron lines are very faint. As might be expected, from the 

 association with sea-water, the lines of sodium and potassium are 

 very bright. A photograph of the flame spectrum shows lines of 

 manganese, and some of the strongest violet lines of iron. 



When some fragments of the nodules are placed along an end -on 

 vacuum-tube and the spark passed, flutings of carbon and lines of 

 hydrogen appear, almost exactly as they do when meteorites are 

 subjected to the same treatment. When the tube is made red hot, 

 the thallium line becomes very bright, and also the yellow and green 

 lines of sodium. 



It will be seen that the spectra of the nodules are somewhat differ- 

 ent from those of meteorites, chiefly in the relative intensities of the 

 lines, but the difference can probably be explained by considering the 

 effect of sea- water. I have the authority of mv friend Professor 

 Thorpe for stating that thallium and manganese would be the most 

 likely of the meteoric constituents to form insoluble compounds, and 

 hence these are what we should expect to find in deep-sea accumula- 

 tions of meteoric dust. The spectroscopic observations therefore 

 seem to show that it is not improbable that the manganese nodules 

 owe their origin, in some part at least, to meteoric dust. 



At the suggestion of Professor Renard I separated some of the 'iron 

 spherules from the nodules by dissolving in dilute hydrochloric acid,. 



