244 A. LIVERSIDGE. 



iron, and present no traces of fusion nor of the skin of mag- 

 netic oxide, usually present on the surface of large masses 

 of meteoric iron. 



The minute fused or round globules of iron met with by 

 Mr. Murray (now Sir John Murray, k.c.b.) in the dredgings 

 obtained by H.M.S. Exploring Vessel "Challenger ," were 

 specially sought for but without success. 1 



On heating the dust in a glass tube it readily blackens, 

 gives off water with a strongly marked alkaline reaction 

 and emits an empyreumatic odour, hence there is a notable 

 proportion of nitrogenous organic matter present, and this 

 is confirmed by its behaviour when heated on platinum foil, 

 for it at once blackens, and the scattered particles of 

 organic matter ignite and are seen as glowing points or 

 sparks running over its surface ; at the same time a well 

 marked nitrogenous odour is evolved. After burning off 

 the whole of the combustible matter the residue is of a 

 reddish clay-brown colour not materially different from 

 that of the original substance. Apart from the larger 

 woody particles, the organic matter must be very uniformly 

 distributed since the dust appears on ignition to blacken 

 equally throughout. 



Under the microscope the dust is seen to be almost 

 entirely composed of small particles between infd-oth and 

 the is^oth of an inch in diameter, or *01 to *02 mm., a few 

 of the coarser grains of sand being about aVth of an inch, 

 or 1 mm. Very few of them are quite opaque, the larger 

 grains are colourless and transparent but most of the 

 smaller particles transmit a yellowish-brown colour; with 

 but very few exceptions the particles are rounded or 

 subangular, as if wind or water worn, and with no recog- 

 nisable traces of igneous fusion. Some diatom frustules 

 are sparingly scattered through the dust, these strongly 



1 Proc. Royal Soc, Edinburgh, 1876, p. 258. 



