OBSERVATIONS OF LUMINOUS .METJiOKS. 211 



The ' Davenport Gazette ' states that another stone fell at Homestead, near 

 Iowa City (lat. 41° 46' N., long. 92° 0' W.), in a field covered with ice and 

 snow, and rebounded in a N.E. direction for a distance of more than thirty 

 feet up a slight declivity, where it came to rest in the sand, which was fused 

 and adhering to it. It weighed originally about 7 lb. 6 oz., but had been 

 reduced by eager curiosity-hunters to 3 lb. 8 oz. ; the fractured surface of 

 this meteorite had a dark and less distinct coating than that belonging to the 

 larger block from which it had been detached by tbe explosion. 



The stones are covered with the usual black crust, and there is evidence on 

 some of the pieces of the meteorites of the fused material of the outer portion 

 having run partially over the freshly fractured surfaces. Some fragments 

 show distinct evidence of a sort of lamination or imperfect stratification, the 

 parts where the surfaces cleaved being smoothed down as if by pressure or 

 friction. About 100 were found, varying in size from 9500' to 50 grammes, 

 25 kQogs. having been sent to Paris, A preliminary chemical examination 

 of this meteorite has already been made by L. Smith, who finds the specific 

 gravity to be 3"57 and the composition : — 



Nickel-iron =12-53, Troilite =5-82, Silicates =S1'G1: totallOO-00. 



The nickel-iron consists of 



Iron=89-W, Nickel =10-35, Cobalt=0-54: total 99-93, 



■with traces of copper, phosphorus, and sulphur. The silicate contains iron 

 protoxide, alumina, magnesia, soda, with traces of lithia and potash, and has, 

 according to L. Smith, very similar compositions to the meteorite of New 

 Concord, Guernsey Co., Ohio (1860, 1st May). Daubrce remarks on its chon- 

 dritic structure, and considers it to belong to a large class of meteorites, 

 notably represented by the stones which fell at YouiUc (1831, May 31st) and 

 Aumale, Algeria (1865, August 25th). 



This meteorite being of the stony kind, and having so recently fallen, it 

 occurred to Wright (see also the examination of the Texas Meteorite, p. 244) 

 to examine the gases contained in the particles of iron distributed throughout 

 its mass, with a view to learning whether they present the same characters 

 as the gases occluded by the iron forming large and independent masses. 



He extracted from this picked iron at a moderately elevated temperature 

 several times its volume of gas, consisting of 35 per cent, of carbonic acid, 14 

 per cent, of carbonic oxide, the remaining 51 per cent, being chiefly hydrogen. 

 These results were obtained from metallic portions removed with the magnet : 

 the pulverized rocky residue, however, retained a considerable amount of iron in 

 too finely divided particles to enable them to lift tlie stony fragments adhering 

 to them ; accordingly a piece of the solid meteoi'ite, about four cubic centimetres 

 in amount, was reduced to powder and placed in the tube attached to the pump. 

 The warmth of the hand sufficed to disengage some little gas, which, when 

 tested, was found to contain carbonic acid and hydrogen. The pump was 

 then set in action, and heat applied to the tube in the following manner : — 

 I. The temperature of boiling water continued for several hours. II. The 

 moderate heat (200°-250°) of a small Bunsen flame applied for a short time. 



III. A stronger heat, kept below visible redness, applied for nearly an hour. 



IV. Low red heat maintained about half an hour. V. Full red heat. The 

 total amount of gas evolved was about two and a half times the volume of the 

 material operated upon, and twenty times that of the iron. The following are 

 the relative proportions of the gases obtained at different temperatures : — 



1875. K 



