26 Annals of the South African Museum. 



A third series of fields differs from the last-mentioned in showing, 

 instead of these grains, small rods with rounded ends, which reach 

 0'2 mm. in width, and are also apparently separated by a border of 

 taenite. As the diameter of the grains coincides with the width of 

 these rods, it may be that we are, in the two cases, dealing merely 

 with variations in the direction of section. On the other hand, how- 

 ever, the frequent occurrence of the granular plessite and the com- 

 parative scarcity of the rod-like variety, as well as the absence of 

 distinct transition forms, tell against this conjecture. Finally, there 

 are other fields which consist half of the one, half of the other kind 

 of plessite. As to the identity of the small grains and rods with 

 the larger bars there can be no doubt. Moreover, it is now generally 

 assumed that plessite is not an independent alloy of nickel and iron, 

 but that it consists sometimes of kamacite only, sometimes of 

 kamacite and taenite in very varying proportions, and it is note- 

 worthy that this Bethany iron affords more conclusive evidence for 

 this view than is usually the case. 



Other portions of the etched plates on general view assume a 

 banded appearance. The bands attain a maximum width of 5'5 cm., 

 and are bounded by lines parallel to the octahedral faces, so that 

 the octahedral structure is preserved. In reflected light alternate 

 bands give a similar and uniform sheen, so that the whole appears 

 homogeneous to the unaided eye. On the boundary of the normally 

 developed portions of the surfaces there is a gradual passage from 

 isolated lamellae, lying parallel to the traces of three different octa- 

 hedral planes, to others which are grouped together until they 

 come to cross one another, and enclose small fields in the usual 

 fashion. 



All these phenomena are distinctly shown on Pigs. 1 and 2, Plate 

 VIII. 



If one examines the homogeneous-looking bands mentioned above 

 with a lens, or, better still, with the microscope, one sees that they 

 include numerous fine taenite-like scales. These vary much in 

 length, and are about 0*02 to 0"03 mm. wide. They divide the 

 bands into anastomosing strips of from 0'07 to 0"25 mm. in width 

 (Plate VIII., Fig. 2). These are not small beams, for they are not 

 completely separated, each portion not being fully surrounded by 

 taenite. The nickel-iron lying between the taenite-like scales shows 

 etching-lines and hollows. On favourable etching one may see that 

 these lines run in three directions, and abut upon the delicate scales, 

 to continue undisturbed, however, on the other side of them. When 

 viewed at such a distance that the finer details are lost, such portions 



