1887.] Researches on the Spectra of Meteorites. 



127 



Comparisons of the foregoing Observations among themselves, and with 

 those made on various Orders of Celestial Bodies. 



The discussions have taken, in the first instance, the form of com- 

 parisons of the different phenomena observed, and for this purpose 

 all recorded observations of flutings and bright lines and dark lines 

 in stars, comets, nebulas, &c, have been carefully mapped in addition,, 

 all records having, when necessary, been brought to a common scale. 

 Having these maps, I could then compare the totality of celestial 

 observations with the laboratory work to which reference has already 

 been made. 



The following are among the comparisons already dealt with : — 



I. The spectra of meteorites observed under the various conditions,. 



chiefly considering magnesium, iron, and manganese, with the 

 bright lines observed at low temperatures. 



The main conclusions are : — 



(1 .) That only the lowest temperature lines of Mg, Na, Fe, Cr, Mn, 

 Sr, Ca, Ba, K, Zn, Bi, and Ni are seen in the meteorites under the 

 various conditions. They are not all seen in one meteorite or under 

 one particular condition; the details of individual observations are 

 fully recorded in Maps 2 and 2a. 



(2.) That in the case of Mg the line most frequently seen is the 

 remnant of the fluting at 500, while in a photograph the main ultra- 

 violet line recorded is the one at 373, previously recorded under these 

 conditions by Messrs. Liveing and Dewar. In the quantity spark 

 other lines are seen, notably Z> 1} 6 2 , 6 4 , and 5201. The line at 500 was 

 considerably brightened when the number of cells was reduced, thus 

 showing it to be due to some molecule which can exist best at a low 

 temperature. 



(3.) That in the case of Mn the only line visible at the temperature 

 of the Bunsen burner, 5395, is the only line seen in the meteorites. 



(4.) That the lines of iron seen in the meteorites are those which 

 are brightest when wire gauze is burned in the flame. The chief of 

 these are 5268, 4383, 5790, and 6024 ; it is possible, however, that 

 the two latter are due to some substance, not iron, common to the 

 gauze and the meteorites. 



II. The spectra of meteorites generally, with the bright lines and 



flutings seen in luminous meteors, comets, and some " stars." 



x. Luminous Meteors. 

 With regard to the records of luminous meteors, it may be remarked 

 that the observations, so far as they have gone, have given decided 

 indications of magnesium, sodium, lithium, potassium, and of the 

 carbon flutings seen in comets. The following quotations from 



