124 



Mr. J. N. Lockyer. 



[Nov. 17, 



F. Experiments upon the Spectra of Meteorites at low Temperatures. 



All the later observations recorded have been made on undoubted 

 meteorites, fragments of which have been in the kindest manner 

 placed at my disposal. 



L In the Oxy hydrogen Flame. 



The observations gave in all only about ten or a dozen lines belong- 

 ing to the metals magnesium, iron, sodium, lithium, and potassium, 

 aud two flutings, one of manganese, and one of iron. 



II. With a Quantity Coil without Jar. 



The observations gave in all about twenty lines belonging to the 

 metals magnesium, sodium, iron, strontium, barium, calcium, chro- 

 mium, zinc, bismuth, and nickel, and four lines of unknown origin. 



III. When heated in a Vacuum Tube when a Current is passing 



along it. 



A small piece of iron meteorite was enclosed in the middle of a 

 horizontal tube, so that the spark might be made to pass through the 

 tube and over the meteorite. After complete exhaustion has been ob- 

 tained, the first spectrum obtained when the tube, end on, is placed in 

 front of the spectroscope, is a spectrum of hydrogen. The carbon 

 nutings are only visible occasionally. If the meteorite then be very 

 gently warmed by placing a bunsen burner at some distance below 

 the tube, the glow over the meteorite is seen to change its colour, and 

 the line at 500 is constantly, and another line at 495, apparently 

 exactly in the position of the second line of the spectrum of the 

 nebulae, is occasionally, seen. This line is less refrangible than the 

 structure line of hydrogen in this region, which occupies the same 

 position as the barium line. This, however, if the heating is con- 

 tinued, especially in the case of stony meteorites, is soon succeeded 

 by a much more brilliant green glow, in which magnesium b and 

 many other lines appear, now accompanied by the carbon flutings. 

 The observations made under all the above conditions are shown in 

 Maps 2 and 2a. 



In these observations if a line in the meteoric spectrum were 

 coincident with a metallic line, with the dispersion employed, in the 

 absence of the brightest line of that metal, the line was regarded as 

 originating from some other substance. Thus a line was sometimes 

 seen at 5480, apparently coincident, with the dispersion employed, 

 with the green lines of Sr and Ni; sometimes the brightest line of 

 Sr at 4607 was absent, and it was then fair to assume that the 

 presence of 5480 was due to Ni, but in the presence of 4607 it might 

 be due to Sr. * ...... 



