OBSERVATIONS OF LUMINOUS METEORS. 249 



observed. They differed, however, somewhat as to the order of their relative 

 intensities from those observed with nitrogen alone. One of the lines appeared 

 to coincide Avith the chief eoromd line 1474 K, although not so sharp as the 

 latter appears in the solar spectrum. An oxygen line likewise observed has 

 the position 14G2 K very nearly, and falls very near the position assigned to 

 a bright coronal line by Denza and Lorenzoni when observing the eclipse of 

 the 22nd December, 1870. A second oxygen line, less bright but shai-p and 

 distinct, has the position 1359 + 1 K. The author directs attention to the 

 complete change which the spectrum of an air-tube undergoes by the intro- 

 duction of hydrogen. According to the method by which Wright calculates 

 the amount of gas present in an iron (see the meteorite of the lied Eiver, 

 Texas, above), "this metal occludes 4-G9 times its volume of mixed gases. 

 Although the greater part of the gas had been removed, the author is of 

 opinion that the whole amount was by no means exhausted. The fact of the 

 volume of gas in this instance being in excess of that obtained by Graham and 

 Mallet probably arises from the Tazewell iron having been in a finely divided 

 state. 



1871, Spring of. — Koda, Province of Huesca, Spain*. 



The exact date of the fall of this meteorite is not given, but it is stated to 

 have occurred during the spring of 1871 , at a spot two kilometres fi-om Eoda. 

 Two fragments in the possession of Pisani weigh about 200 grammes, aud 

 appear to have formed the half of a stone which was of the size of a fist. It 

 is covered with a black crust, which is continuous and brilliant in places 

 where this species of lustrous varnish has run. The interior is ashy grey, 

 with greenish grains resembling peridot (some several millimetres in diameter) 

 scattered throughout the mass. The grey surface is, however, not of a uni- 

 form tint, but presents two irregularly shaped areas, one being grey, the other 

 yellowish grey. The stone is very friable, and has no action on the magnetic 

 needle. Before the bloA\inpe it is fusible, becoming black and feebly magnetic. 



Only a small portion, 14-75 per cent., of the meteorite is broken up by acid, 

 that unacted upon amounting to 85-97 per cent. Below are given, in addi- 

 tion to the composition of the constituents separated by acid, tbe results of an 

 analysis of the minerals constituting the mass of the stone : — 



SiOs Al.Oj Cr^Oj FeO C'aO MgO K,0 and Na,0 S 



A. Soluble... 38-85 481 24-27 821 23-86 =100-00 



E. lusoluble 52-93 1-95 039 16-29 1-92 26-52 =10000 



C. Total 51-51 2-30 034 17-04 231 26-61 080 040 =101-31 



The soluble portion appears to be an iron olivine, mixed probably with a 

 little anorthite ; the insoluble portion consists chiefly of bronzite, or, accord- 

 ing to Pisani, probably hypersthene, with the specific gravity of which mineral 

 that of the meteorite more closely accords. The sulphur and the chromium 

 are, it is presumed, present as magnetic pyrites and chromite ; no nickel 

 whatever M-as detected. 



The yellowish green grains were very slightly attacked by acid, only 6 per 

 cent, being soluble in that reagent. Their composition proved to be : — 



Silicic acid 51-10 27-3 



Alumina 2-83 1-3 



Iron protoxide 27-70 '■'^'■'ll4-9 



Magnesia 17-20 38 / 



98-83 

 » F. Pisani, ' Coinpt. Eend.' Ixsix. 1507 ; G. A. Daubree, ' Compt. Eeud.' Ixxix. 1509. 



