. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. 28 Annals of the South African Museum. In three places at least I noticed the presence of platy inclusions, 0-1 mm. wide, which have a bluish-black colour and a strong metallic lustre by reflected light. There is no doubt that these are daubr^elite. The plates have irregular boundaries, and are orien- tated obliquely to the longest diameter of the troilite. Schreibersite occurs as tiny spangles or little zigzag rods, lying as a rule wedged in between the bars, and in one place it forms a plate- like
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. 28 Annals of the South African Museum. In three places at least I noticed the presence of platy inclusions, 0-1 mm. wide, which have a bluish-black colour and a strong metallic lustre by reflected light. There is no doubt that these are daubr^elite. The plates have irregular boundaries, and are orien- tated obliquely to the longest diameter of the troilite. Schreibersite occurs as tiny spangles or little zigzag rods, lying as a rule wedged in between the bars, and in one place it forms a plate- like piece, 7 mm. long. This is perhaps one of the so-called Eeichenbach lamellse; that is to say, it lies possibly parallel to a cube face. The small amount of phosphorus in both analyses made, 0'06 per cent., shows that the schreibersite is really only sparingly pre- sent, not that it is merely very indistinct. The accessory constituents are found only in the portions showing numerous lamellae. They are the first to crystallise out, and are followed by the lamellss, which group themselves around them. The plessite forms last, and it therefore appears to me that the absence of troilite and schreibersite in those portions that are not lamellar, indicates that they are com- posed of plessite. In order to ascertain if the small glistening scales which lie in these non-lamellar portions are to be regarded as taenite, I had two analyses made by Dr. Fahrenhorst. Table I, gives the composition of one piece, which showed the structure characteristic of a finely lamellar octahedral iron ; Table II. that of a piece without lamellas. As these showed no essential differences, the sparingly occurring accessory constituents were determined only once. Neither piece left any residue in aqua Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble t
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
