542 Geological Society : — 



The relative intensities and distinctive characters of the lines are 

 represented by figures and letters, placed against the numbers in the 

 Tables. 



The spectrum, which extends from a to H, is divided, and forms 

 two maps. The air-spectrum and the principal solar lines are placed 

 at the top of each map, and below these the spectra of the following 

 metals : — Sodium, potassium, calcium, barium, strontium, manga- 

 nese, thallium, silver, tellurium, tin, iron, cadmium, antimony, gold, 

 bismuth, mercury, cobalt, arsenic, lead, zinc, chromium, osmium, 

 palladium, and platinum. 



The lines of the air-spectrum are referred to the components of 

 air to which they severally belong. An unexpected result was ob- 

 served : two strong lines of the air-spectrum, one of them a double 

 line, were seen to be common to the spectra of oxygen and nitrogen. 

 These gases were obtained from different sources with identical results. 

 The strong red line of the air-spectrum is shown to be due to the 

 presence of aqueous vapour, and to coincide with the line of hydro- 

 gen. The carbonic acid in the air is not revealed by spectrum 

 analysis. 



Three pairs of lines and one band of haze are given in the sodium 

 spectrum in addition to the double D line. As these might be due 

 to impurities of the commercial sodium employed, the observation 

 was confirmed by an amalgam of sodium prepared by the voltaic 

 method from pure chloride of sodium. Two of these pairs of lines 

 have been recognized in the spectrum of a saturated solution of 

 pure nitrate of soda. 



The two stronger pairs appear to agree in position with solar lines 

 having the following numbers in KirchhofFs scale : — 864*4 and 867*1, 

 and 1150-2 and 1154*2. 



The spectrum from electrodes of potassium contains many new 

 lines. For the spectra of calcium, lithium, and strontium, metallic 

 calcium, lithium, and strontium were employed. 



Barium was mapped from an amalgam of barium prepared by elec- 

 tricity from chloride of barium. 



The following metals were employed in the form of electro-deposits 

 upon platinum : — manganese, silver, tin, iron, cadmium, antimony, 

 bismuth, cobalt, lead, zinc, and chromium. Care was taken that the 

 other metals should be reliable for purity. 



GEOLOGICAL SOCIETY. 

 [Continued from p. 4 7 7- J 

 February 3, 1864. — Professor A. C. Ramsay, President, in the Chair. 

 The following communication was read : — 



" On the Permian Rocks of the North-west of England, and their 

 Extension into Scotland." By Sir. R. I. Murchison, K.C.B., F.R.S., 

 F.G.S., and Professor R. Harkness, F.R.S., F.G.S. 



