272 



NATURE 



IJuly 27, 1876 



Mr. Power suggests that the brittleness of iron in cold weather 

 may perhaps arise from somewhat similar molecular groupings 

 occurring within the metal whilst it contracts in cooling. 



One must, however, recollect that water expands when cooled 

 from 39° Fahr. down to the freezing-point. To this the action 

 of cold upon iron affords no parallel, for cold renders the metal 

 more dense. Cold brings the atoms into closer connection ; 

 hence cold will (presumably) tend to augment the strength of 

 their mutual attraction. H. M. Adair 



July 18 



Habits of Parasitic Crab 



Some days since I obtained in the trawl a large specimen of 

 the common Ascidian {A. Virginea) and kept it alive for about 

 a week. It contained a specimen of the small Parasitic Crab 

 {Pinnotheres pisum) about the size of a threepenny piece. The 

 crab came out every night to feed about the floor of the tank, 

 and found lodging during the day, as I afterwards proved by 

 dissection, in the branchial cavity of the Ascidian. The crab 

 is commonly found in the mussel, but I was not aware before 

 that it ever wandered abroad, or sought food except within its 

 tenement. W. S. G. 



Kenmare 



THE ROWTON SIDERITE 



"AN addition of exceptional interest has recently been 

 ■**- made to the collection of meteorites in the British 

 Museum, by the presentation, on the part of the Duke of 

 Cleveland, of a siderite (iron meteorite) which fell on his 

 Grace's property at Rowton, near Wellington, in Shrop- 

 shire, about seven miles north of the Wrekin, on the 

 20th of April last. At about twenty minutes to 4 o'clock 

 on the day mentioned, a strange rumbling noise was 

 heard in the atmosphere, followed almost instantaneously 

 by a startling explosion resembling a discharge of heavy 

 artillery. There was neither lightning nor thunder, but 

 rain was falling heavily, the sky being obscured with 

 dark clouds for some time both before and after the 

 incident narrated. About an hour after the explosion, 

 Mr. George Brooks, stepson of Mr. Bayley, had occasion 

 to go to a turf field in his occupation adjoining the 

 Wellington and Market Drayton Railway, about a mile 

 north of the Wrekin, when his attention was attracted to 

 a hole cut in the ground. Probing the opening with a 

 stick, Mr. Brooks discovered a lump of metal of irregular 

 shape which proved to be a meteorite weighing 7f lbs. 

 It had penetrated to a depth of eighteen inches, passing 

 through four inches of soil and fourteen inches of solid 

 clay down to the gravel — conclusive evidence of the force 

 of its impact with the earth. The hole (which has been 

 protected for further investigation) is nearly perpendicular, 

 and the stone appears to have fallen in a south-easterly 

 direction. Some men were at work at the time within 

 a short distance, and they, together with many other 

 people in the neighbourhood, heard the noise of the ex- 

 plosion." 



The above account is taken from the Wolverhampton 

 Chronicle, and a further notice is given in the Birming- 

 ham Daily Post of a meeting of the Natural History 

 Society of Birmingham, at which meeting Mr. Brooks, 

 accompanied by Mr. Gibbons, of Wolverhampton, and 

 Mr. Wills, exhibited the meteorite. Mr. Wills described 

 the circumstances attending the fall, stating that the 

 "sound was heard as of something falling during a heavy 

 shower of rain accompanied by a hissing and then 

 a rumbling noise;" he further stated, "that when Mr. 

 Brooks found the mass it was quite warm." Mr. Wills 

 described it as " being black on the surface, and appa- 

 rently covered with a scale of metallic oxides ; but at the 

 point where it impinged on the earth the oxides had been 

 removed, and the metallic character of the mass had been 

 revealed." 



To these interesting and accurate observations, made 



by the "gentlemen of the locality, I have the pleasure of 

 adding that I believe it was very much owing to a reso- 

 lution passed by this valuable local society, at the sug- 

 gestion of the gentlemen whose names have been men- 

 tioned, to which must be added that of the well-known 

 petrologist, Mr. Allport, of the Rev. H. W. Crosskey, and 

 Mr. Woodward, that Mr. Ashdown, the agent of the 

 Duke of Cleveland, took action in the matter, and ob- 

 tained his Grace's assent to the meteorite being presented 

 to the trustees of the British Museum. 



On its arrival in this department it was with no small 

 pleasure that I found the description of Mr, Wills was in 

 all points accurate. It is, indeed, an iron meteorite, and 

 the special interest of this statement lies in the fact that 

 though our great collection of 311 distinct meteorites at 

 the museum contains 104 indubitable iron meteorites, the 

 falls of only sevc n of the latter were witnessed. 



The collection contains eight stony melforites that 

 have fallen in the British Islands ; but the Rowton 

 meteorite is only the second iron meteorite known as 

 having been found in Great Britain. 



It is thus not without a keen curiosity that one inspects 

 a freshly fallen fragment of iron just arrived from space 

 in our own country. One hastens to ask of it what 

 impression the action of the atmosphere has made upon 

 its surface during its brief transit, since most of our vfovi 

 meteorites have undergone long weathering in the earth. 

 Mr. Wills, however, has given that answer. The meteo- 

 rite was covered with a very thin pellicle of the jet-black 

 magnetic oxide of iron, and only where this had been 

 rubbed off by abrasion with the soil is the bright metallic 

 surface of the nickeliferous iron revealed. The little 

 meteorite has all the usual appearance of being a frag- 

 ment. Irregular and somewhat angular in form, with its 

 edges rounded, no doubt, by the fusion and removal of no 

 inconsiderable part of its material in its encounter with 

 the atmosphere, it presents but very slight traces of the 

 finger-and-thumb marks which so characteristically pit the 

 surfaces of most stone and of some iron meteorites. 

 Furthermore, there are fissures which penetrate deeply 

 into the iron mass and bear testimony which there can 

 be no gainsaying to the action of disruptive forces of tre- 

 mendous strength durins^ the hot encounter of the original 

 mass with the atmosphere, and of which one explosion, 

 and the rumbling echoes, possibly, of others, recorded by 

 the witnesses bear evidence. The form of one of these 

 fissures throws instructive light on the cause of the pitted 

 surface of meteorites. The depth to which the little mass 

 penetrated a stubborn soil is proof of how much momen- 

 tum still remained to it, partly due, no doubt, to the 

 approximately vertical direction in which it penetrated 

 the atmosphere, and in some degree, too, to the higher 

 density of an iron mass as compared with one of stone, 

 the stony meteorites rarely penetrating to so considerable 

 a depth. This depth of penetration and the direction of 

 the little mass in space near north to south offer close 

 resemblance between this iron and the iron meteorite of 

 NedagoUa, in India. 



There are indications on the metallic surface of the 

 composite crystalline structure revealed by etching iron 

 meteorites with acids, and known as the Widmannstattean 

 figures, the results of the separate crystallisation of dif- 

 ferent alloys, often demarked in some of their surfaces 

 by plates of metallic phosphides. 



The development of this structure and the consequent 

 determination of the particular type of iron meteorite to 

 which the Rowton siderite belongs, as also the analysis of 

 the iron itself, can only be carried out after a small por- 

 tion of the meteorite shall have been carefully cut off by 

 the aid of a lapidary's wheel, a process requiring in this 

 particular case some careful precautions to prevent rust 

 being hereafter formed and to reduce the loss of material 

 to a minimum, 



N. S. Maskelyne 



