Spectrum Analysis of Magnesium and Carbon. 343 



Mr. Edward Stallibrass, in a valuable paper on Deep-sea 

 Sounding in connexion with submarine Telegraphy*, says : — 

 "Of all bottoms these oozes are the ones to be preferred. 

 The fact of their being found shows that no currents exist in 

 those parts, and they are so soft that the cable sinks far down 

 into them. The old idea that currents do not exist at any 

 great depths has long since been rejected. Currents may 

 exist at almost any depth. Between the Canary Isles there 

 are strong currents 1000 fathoms below the surface, and their 

 scouring action may be clearly detected." 



Mr. J. Y. Buchanan, in the discussion on Mr. Stallibrass' 

 paper, also said: — " If we find hard ground we know that there 

 must be something to prevent the accumulation of sediment. 

 Now the only thing that prevents the accumulation of sedi- 

 ment is a current ; and one help that telegraph soundings 

 have thus given to geographical science is the indication that 

 tidal currents exist even at very great depths in the open 

 ocean." f 



I have very little doubt that these currents are of tidal 

 origin. Mere differences of specific gravity in the ocean water, 

 whether due to temperature or salinity, are insufficient, in my 

 opinion, to produce such rapid currents ; but the arrest and 

 concentration of the immense mass of ocean water set in move- 

 ment by the attraction of the sun and moon are more potent 

 influences. The comparative neglect of tidal action as a geo- 

 logical cause is doubtless due to our usually looking at the 

 tides as superficial currents ; whereas, unlike currents of the 

 Gulf-stream type, they extend to the bottom of the deepest 

 oceans. The subject is one capable of much development ; 

 and numerous other illustrations could doubtless be brought 

 forward to fill up this merely outline-sketch which would sus- 

 tain the main principle I have sought to establish, namely, that 

 tidal action as a physical agent is not confined to coasts and 

 shallow seas and estuaries, but is a widespread and potent 

 cause of geological change. 



XLYI. Mathematical Spectral Analysis of Magnesium and 

 Carbon. By Dr. A. Gkunwald. {Abstract.) 



[For this Abstract the Editors are greatly indebted to Prof. Liveing.] 



THE author's method of analysis consists, in general, in 

 tracing a simple numerical relation between the wave- 

 lengths of some of the lines in the spectrum of one substance A, 

 and those of lines in the spectrum of some other substance B. 



* Journ. of the Society of Telegraph Engineers, p. 509 (1887). 

 + Ibid. p. 514. 



2 A2 



