44^2 PROF. NOKDENSKIOLD, EXPEDITION TO GREENLAND. 



its surface, and ultimately, when unpacked two months later in 

 Stockholm, crumbled to a reddish-brown powder, consisting 

 partly of a fine rust-powder, partly of angular bits of iron, rusty on 

 the surface, and varying in magnitude from the size of a pea to 

 that of a hemp-seed. An entirely unchanged, and therefore, on 

 fresh fracture still metallic, portion of Stone 4, began at one 

 corner to rust, swell and crumble, while the remainder of the 

 iron remained unaltered. The rust spread itself like a fungous 

 growth over the rest of the piece, and extended itself to the interior, 

 which thereupon swelled and crumbled like an efflorescent salt. 

 During this time the weight of the piece of iron increased. 



Weight of a fragment of iron when packed - 29" 935 gr. 

 „ „ after 129 days - 30-143 gr. 



Weight of the unchanged iron - - 24 * 529 gr. 



so that 5*406gr. had weathered away to a rusty-brown powder 



and during this time had increased in weight 0*208 gr. or 3*8 per 



cent. 



In a hermetically sealed glass tube the iron was completely 



unchanged. 



In a glass tube, that had been hermetically sealed, but in which 



a fine crack had taken place in cooling, the iron continues to 



crumble. 



In a eudiometer over mercury, the iron in a few days absorbed 



a considerable amount of oxygen, in consequence of which the 



mercury rises in the tube. 



In alcohol, the iron does not crumble. In water, it rusts, but 



does not appear to fall to pieces. 



In air dried by sulphuric acid the crumbling process takes place 



slowly. 



Varnishing does not fully protect these pieces of iron from 



weathering, not even if immersed in warm copal-varnish. I 



thought at first that the cracking was the result of the contracting 

 and shrinking of the mass, but this is not the case. On the con- 

 trary, the cracking is caused by dilatation. With what force this 

 operates may be judged from the fact, that a piece of iron, on 

 which chisel and saw are used without effect, is broken or bent by 

 the decomposition of the mass. In general, cracks first appear at 

 right angles to the surface of the stone ; these diverge as from a 

 centre, and, at a depth of a few lines below the surface of the stone, 

 meet a crack that runs parallel with the surface, ^vhich, by the 

 swelling of the overlying crust, is soon formed into a little dome, 

 sometimes an inch in height. In the meantime the overlying 

 crust is raised, doubled up and broken in a manner which bears a 

 striking likeness to the doubling of the stratified rocks by the so- 

 called eruptive forces, — that is, if one supposes that the cracks, 

 instead of being empty, are filled with detritus, which gradually 

 hardens to an " eruptive " rock. 



When fragments of the largest stone, weighing 134 gr., were 

 heated to redness, they parted with nearly two litres of gas, or 

 about 100 times the volume of the iron, as also a considerable 

 amount of water, which, like the gas, had a bituminous smell. 



