180 ROCHESTER ACADEMY OF SCIENCE. [June 8, 
For comparison the analyses of kamacite and tzenite are given, each 
next to its corresponding part of the plessite. 
Kamacite. Plessite. Teenite. 
amet = = 
Kamacite-like part. Teenite-like part. 
Fe 93.09 92.81 72.98 74.78 
NZ) .6:6g Ry 25.87 24.32 
Co 325 .19 83 36 
Ee 102 19 Qt 50 
100.05 100 16 100.59 99-93 
These physical and chemical correspondences justify, I think, the 
conclusion that in the Welland siderolite there are but two distinct 
nickel-iron alloys, viz.: kamacite and teenite, and that the so-called 
plessite is merely thin alternating lamellz of kamacite and tenite. 
It is unsafe to generalize on a single analysis; but an examination 
of the markings ot other meteoric irons suggests the thought that in 
them also there may be but two distinct alloys. Such are the Descubri- 
dora, the Glorietta Mt. and notably the Kiowa County, and the Augusta 
County, Va. meteorites. In sections of the last two irons in Ward & 
Howell’s collection every piece of so-called plessite in the Augusta 
County iron shows its thin lamella, and in the Kiowa County pallasite 
the gradations of the markings are such that in parts of the iron it 
would be difficult to say which should be called kamacite and which 
plessite. 
In etching meteoric iron the kamacite is attached by acid more 
readily than the teenite, richer in nickel. The tenite and plessite stand 
in relief. Where lamelle do not show in plessite it may be that closely 
crowded tznite bands have protected neighboring kamacite layers from 
acid action, and more careful or prolonged etching might perhaps 
develop lines in plessite that now appears homogeneous. 
Remarks upon the paper were made by Mr. E. E. Howell and the 
President. 
In the absence of the author, Mr. J. G. D’Olier read the following 
paper. 
