Árbók Hins íslenzka fornleifafélags - 01.01.1965, Page 103

UNDERS0KELSE av fibre
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1. Surface Structure.
Fig. 2, upper left, shows photos of film prints from Snæhvammur. Only one
Photo of the weft is shown because of the bad condition of preservation of this
thread. For comparison two photos are shown from the very fine broken lozenge
twill from Oseberg (029a), two from a skein of yarn from Oseberg (083),
further prints from some recent material: mohair No. 85 and 86, Turkey, (Franckhs
Werkstoff-fiihrer), and Icelandic modern sheep.
From Fig. 2 the fibres from 3931 and 029a are shown to be very similar,
with smooth edges, the scales overlapping very slightly. The surface structure
Pattern is irregular mosaic, relatively close. The borders between the scales
are in general smooth but partly characteristically crenate and rippled. The
crenate type of cuticular pattern is very characteristic of the recent mohair
type of wool, as opposed to the polygonal pattern of all recent sheep surface
structures. (Cf. Doehner-Reumuth, p. 18, Fig. 10—11). The pattern suggests a
fiber of mohair type or a fiber of a sheep now unknown. Recently found material
from the Near East may help to elucidate this problem.
2. Measuring of Fiber Dimensions.
Because of the bad condition of the fibres, they could only be cleaned in xylen.
They were measured in paraffine with an occular 6.3x pl. and objective 63x pl.
From these measurements a distribution curve of diameter dimension was construc-
ted.
By spinning and weaving it is particularly important to have fibres which do
not vary too much. The regularity can be indicated by the variation coefficient V%.
Variation coefficient V% = ------- 100%
M
Middle value
Standard
deviation

Mjí =
xt + k2 + x3 .... xn
Ý
(xj — m)2 + (x2 — m)2 + (x3
m)2
n — 1
(xn — m)2 n
By calculating variation coefficient and middle value, a quality evaluation of
the fibres can be obtained. The lower the middle value of the fibre diam. and
the variation coeff., the higher the quality (Fig. 3). A very high quality may be
the result of a high technique in sorting wool. This seems to be the case with
the weave 025 from Oseberg, which has a surface structure like the modern
Icelandic sheep and middle value and variation coeff. like merino.
Fig. 3 shows distribution curves for some modern wool samples and Snæ-
hvammur. The mohair and the Icelandic sheep are unsorted, for merino this
's not known. The mohair sample belongs to the coarser type. Mohair fibres are
°f extraordinary smoothness and do not felt. This is also characteristic of the fine
lozenge twills. The Snæhvammur quality is quite close to mohair, but the curves
<3o not give any unambiguous conclusion about the fiber.
Pig. 4, curves from the same type of weave in Oseberg and Hyrt (Norway),
Sive interesting details. The two eoarser ones, 044 and OLIIIaa show the surface
structure of ordinary sheep wool fibres. The weft in 044 is finer than the warp.
The quality of OLIIIaa is the same as for primitive sheep. Of all examined fibres
Hyrt has the highest quality. The surface structure is different from ordinary
sheep’s wool, and similar to 029a and 3931.