NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
September, 1954] K. N. RAMCHANDRAN AND P. R. YERI 153
of the fibre is then recorded in millimeters. Diameter is the distance measured
from one edge of the image of the fibre to the other. In case where both the edges
of the image cannot be focussed at the same time, one edge is focussed first and the
mark of the ruler is adjusted against this edge. The other edge will be focussed
without disturbing the ruler and diameter is recorded. Every fibre in the field of
view is measured. The following convention is observed in the measurement of
fibre diameter.
(a) The measurement is not to be taken at the point where the fibres cross
one another.
(b) If the length of the image is less than the circle (7 cm. diameter) the
measurement shall only be taken when the image will project suffi
ciently beyond the width of the ruler.
(c) A damaged fibre is not measured.
(d) If the fibre measures to a fraction of a division the fibre will be recorded
in the lower group, if less, then half the division and in the higher
group, if more than half the division.
(e) The movement of the slide on the stage is so adjusted as to divide the
slide into eight traverses length at equal distances measuring not less
than 25 fibres in each traverse. The fibre pieces from all the positions
shall be arranged into frequency distribution.
The mean fibre diameter and standard deviation is calculated by using the
following formula. An example is worked out in the case of length measurement
to show the application of the formula.
Mean diameter D=B-m(F1-1)
Standard deviation m√(2F2÷F1—F1 2 )
where
D=Mean diameter
B=Highest group-mean for which a frequency value is recorded
K=Number of groups
m=Class-interval
n=Total number of observations recorded
F1=Sum of the first cumulative values divided by 'n'
F2=Sum of the second cumulative values for the first (K—1) groups divided
by 'n'
If the value of 'n' is very high, the S. D. is calculated by the formula given
above ; if 'n' is not very high, the value obtained by this formula has to be.
multiplied by n/n—1 to get the correct value.
The mean and the standard deviations are also calculated by the following
formula : .
Mean = ± Σ(fx/n X m)
n
S. D. = √Σ X f 2 —(Σxf) 2 /n — 1 x m
154
METHODS OF ANALYSIS OF WOOL FIBRE [Vol. XXIV, Part III,
where
g=group-mean
x=Observed frequency
b=Any arbitrarily chosen value corresponding to one of the group-means
f =g—b/ m
The application of the formula is made clear by the following example :
Interval in microns
10—14
14—18
18—22
22—26
26—30
TOTAL
Group-mean
g
12
16
20
24
28
Observed
frequency
x
5
30
44
15
6
100
Class No.
f
—2
—1
0
+ 1
+ 2
fx
—10
—30
—40
15
12
+ 27
—13
f 2 x
20
30
..
15
24
89
Mean
= 20 — 13 x 4/100 = 19.48
S. D. = √89 — 13 2 /100 X 4 = 3. 76
Cross-Section method
In the diameter measurement by the cross-section method, the Hardy's sec
tioning device (Plate VI, Fig. 2) is made use of. A lock of approximately 200 fibres
which is scoured as usual in warm benzene are inserted in the slot of the holder
and the required length of fibres (about 150 microns) are ejected out with the help
of the turning knob. Fibres are cut flush to the plate. An embedding medium
is applied to the protruding fibres and when it dries, the cross-sections are obtained
with the help of a sharp razor blade. The cross-sections so obtained are cleaned
and mounted on the slide using cedar wood oil as the medium. The diameter of a
given number of fibres is estimated by recording the diameter at the major and the
minor axis of the fibres with the help of a bi-diameter scale.
As the method is not rapid and requires considerable skill, the method of cross-
section is obtained by the modified Hardy's method. In this, the fibres in the
slit are cut flush to one side of the plate and on the other side of the instrument,
the black embedding medium is applied to the fibres. When dry, the fibres are
cut plain to the surface of the plate and the whole is placed on the stage of the pro-
Indian J. vet. Sci., Vol. XXIV, Part III ]
PLATE
VI
FIG. 1. Wira Projector
FIG. 2. Hardy's Sectioning Device
Indian J. vet. Sci., Vol. XXIV, Part III ]
PLATE
VII
FIG. 1. Length measurement apparatus
FIG. 2. Torsion balance
156
METHODS OF ANALYSIS OF WOOL FIBRE [Vol. XXIV, Part III,
groove of the lead screw, pressing lightly at the same time against a fixed fence
extending the length of the screw. The rotating screw draws the forceps, drawing
with them the single fibre, along the length of the screw. The fibre draws through
a lightly loaded jaw to be seen at the near end of the machine. This incorporates
a sensitive trip arrangement which stops the rotation of the lead screw when the
end of the fibre is drawn through the jaw. The forceps are then at a distance along
the screw which is the length of the fibre.
In the simple form of machine without counter, this distance is read off a scale
and noted. This routine is obviated when the counter is employed since this is so
arranged that the operation of lifting the forceps out of the screw moves a counting
wheel corresponding to that length, one step forward. Thus, examination of the
state of the counter following measurement of all the individual fibres of a sample,
shows immediately the number of fibres of each length category in the sample.
The counter is the arrangement of ratchets and pawls visible in the photograph
behind the lead screw.
The machine is arranged to measure fibres upto 30 cm. length in steps of
½ cm., and operates from a normal 200/250 v., 50 cycle, A. C. supply, the power
consumption being negligible.
The mean length and the standard deviation is calculated by the formula :
Mean length L=B-m(F1-1)
Standard deviation = m. √(2F 2 +F 1 —F 1
2
)
where
L=Mean length
B=Highest group-mean for which a frequency value is recorded
K=Number of groups
m=Class-interval
n=Total number of observations recorded
F1=Sum of the first cumulative values divided by 'n'
F2=Sum of the second cumulative values for the first (K—1) groups divided
by 'n'
The following example will facilitate the understanding of the above furmula :
Group-mean
3.75
4.25
4.75
5.25
5.75
6.25
6.75
7.25
7.75
8.25
8.75
9.25
9.75
10.25
10.75
Interval in cm.
3.5—4.0
4.0—4.5
4.5—5.0
5.0—5.5
5.5—6.0
6.0—6.5
6.5—7.0
7.0—7.5
7.5—8.0
8.0—8.5
8.5—9.0
9.0—9.5
9.5—10.0
10.0—10.5
10.5—11.0
Observed frequency
2
7
6
7
4
10
14
18
13
15
14
5
6
4
3
128
First cumulation
2
9
15
22
26
36
50
68
81
96
110
115
121
125
128
1,004
Second cumulation
2
11
26
48
74
110 160
228
309
405
515
630
751
876
..
4,145
September, 1954] K. N. RAMCHANDRAN AND P. R. YERI 157
Mean length L
=B-m(F1-1)
=10.75—0.5(7.85—1)
=7.325 cm.
Standard deviation = m √2F 2 +F 1 —F 2
1
= 0.5 √(2 x 32.40)+(7.85)—61.62
=1.66 cm.
The mean and the standard deviations are also calculated by the following
formula:
Mean = b ± (Σfx/n X m)
S.D. =√Σxf 2 -(Σ xf) 2 /n-1-m
where
g=Group-mean
x=Observed frequency
b=Any arbitrarily chosen value corresponding to one of the group-means
f= g-b/m
The mean staple length is expressed in centimetres and a variation of 0.5 cm.
in either side is tolerated.
FLEECE DENSITY
Fleece density is defined as the number of fibres grown per unit area on the
skin of sheep. It indicates compactness and hence is a useful criterion in judging
wool-carrying capacities of sheep qualitatively and quantitatively.
Sampling
Sampling of wool from the body of sheep for this attribute should aim at collect
ing all the fibres from a definite area of the skin. Very few instruments are available
which function efficiently. A simple device which gives correct results and is easy
for handling, consists of a small brass plate with handles. In the centre of the
plate there are four holes which enclose exactly an area of four square centimetres.
This block, a bottle of Indian ink, a pair of knitting needles, a fine pointed needle
and a dozen of hair clips complete the apparatus. The block is held in position at
the place of sampling and four points are tattooed with the help of the fine needle
with the Indian ink through the four holes in the block. The position of the block
is held taut and the animal is prevented from moving. Care is to be taken while
tattooing and the four corners are to be well demarked. The block is removed and
the fibres in the four tattooed corners are parted so that the sample of fibres is
enclosed in the given area. The hair clips are used to keep away the fibres around
the periphery of the sample. The central lock is cut close to the skin by a fine pair of
pointed scissors. The process of sampling is repeated in the regions of neck, wither,
shoulder, side, back and britch to get the variation within the animal,
PLATE VIII
[ Indian J. vet. Sci., Vol. XXIV, Part III
FIG. 1. Medullometer
FIG. 2. Rapid regain apparatus
September, 1954] K. N. RAMACHANDRAN AND P. R. YERI 159
model No. 495). The photo cell is fitted on a clamp and facilitates adjustment to
right focus. The current produced in the photo cell is conducted to a mirror gal-
vanometer of sensitivity 2.73 X 10 9 micro amp. through two resistances of 10,000
and 50,000 ohms connected in series. The former resistance is used to its maximum
to protect the photo cell and the latter by its adjustment, enables to get desired
deflection on the graduated ruler.
A gram of fully hairy fibres is used in practice as a standard to give maximum
deflection. The grey standard surface on which the benzene tray is placed will
also serve as a standard to give a certain fixed deflection. The resistance of 50,000
ohms is adjusted to give deflection of 25 cm. when the standard sample is exposed
to the light. The deflection when the benzene tray and glass plate are exposed is
noted as zero reading. Benzene with refractive index 1.490 to 1.495 is used.
About half a gram of the sample, taken either from the body of the sheep or the
sample obtained from the bale after zoning, is taken for tests, after thorough
scouring. It is spread in the tray over a surface of 4 X 5 inches in the centre of the
tray and is exposed to the light and the deflection is recorded. The true deflection
of the sample is obtained by deducting the zero reading from the total deflection.
The deflection in centimeters calculated for one gram of sample is called the 'Photo
electric index'.
The index is a relative number corresponding to the extent of
medullation when the maximum hairy sample is taken as a standard.
The medullometer provides only an empirical index of medullation. Hairiness
is dependent on the volume of medullation structure and the index of reflection
obtained in the medullometer does not take into account this factor.
In the
diameter observations with the projector, the diameter of the fibre and the
medullated part is recorded separately for each fibre. Two hundred readings taken
for each slide and the number of medullated fibres along with the medullated part
enables the estimation of medullation percentge by applying the following
formula:—
Medullation percentage = Mn ( Me a n m 2 + S m 2 ) / Fn (Meanf 2 +sf 2 )
100
where
Mn = Number of medullated fibres
Mean m = Mean diameter of the medullated part
Sm = Standard deviation of the mean medullated diameter
Fn = Total number of fibres
f = Mean diameter of fibres
Sf = Standard deviation of mean diameter of fibres
This formula gives the proportion of medullation in relation to the total volume
of the fibre.
CLEAN WOOL YIELD OF RAW WOOL
The estimation of clean wool yield is important in that the bulk of wool pur-
chases is based on the yield of scoured wool, from a consignment. Indian wools in
general, though light in grease content, have a high proportion of vegetable matter,
tags, dags, sand and dirt.
57 AR/54 5
160
METHODS OF ANALYSIS OF WOOL FIBRE [Vol. XXIV, Part III,
Sampling. Usually sampling from a sheep is carried out at the time of shearing.
About 5 gm. of wool is collected from the different parts of a fleece. In the case of
sampling from a bale, approximately eight pickings of four ounces each are pooled
together to form the final sample.
Procedure. A weighed sample of wool obtained as above, is opened thoroughly
either by hand or by mechanical means so that wool is free from all the adherent
impurities. The opened wool is scoured in a series of four wash bowls of four
litre capacity each and preferably made of copper or stainless steel. Each bowl
has an inner perforated bowl which enables loose particles of sand and dirt to fall
on the bottom while scouring. Usually there is a clearance of at least 2 in. between
the inner and the outer bowl. The first three of the bowls contain scouring solutions
with three grams of soda ash and 1 gm. of neutral soap per litre. The temperature
of the liquor is maintained at 50°C. The wool is gently agitated for 15 minutes in
each bowl and squeezed between the rollers of a wringer before it is passed on to the
next bowl. After rinsing the wool in the last bowl which contains pure water, it
is thoroughly squeezed and dried in an oven at 65°C. The wool is then weighed
accurately, and the process of drying and weighing repeated tillt two consecutive
weighings do not differ by more than 0.5 per cent. The percen age of clean wool
yield is calculated by the following formula :
Percentage of clean wool=W2/W1x100
where
W1 = Gross weight of the sample
W2 = Weight of the sample after scouring
The temperature and the humidity of the room are recorded.
DETERMINATION OF MOISTURE CONTENT IN RAW WOOL
Wool being hygroscopic, can absorb moisture to a considerable extent. The
wool buyer is very careful in that he pays money only for wool and not for
water. Hence it is his practice to determine the moisture content in a sample
of wool, drawn from a bale.
Apparatus. The apparatus (Plate VIII, Fig. 2) for moisture content determina-
tion consists of an electric hot air dryer and a blower which impels a stream of hot
air through the sample of wool at a temperature ranging from 80 to 100° C. The
temperature can be set as desired by a lever arrangement. The dryer is
provided with an aluminium container which can be sealed with sealed spring caps.
The container is weighed correctly and the humidity and temperature of the
room recorded. The wool, which is sampled as described in the method for deter-
mination of clean wool yield is kept in the container and reweighed. The di-
fference of the two weights gives the weights of the sample. The container is fitted
to the dryer and temperature of the hot dryer is adjusted to 105°C. The apparatus is
switched on and the hot air is allowed to be blown through the wool for five minutes.
The container is removed, sealed with the cap and is weighed accurately. Again
the process is repeated by placing the container in the dryer so that any two conse-
cutive weighings do not differ by more than 0.5 per cent which confirms that the
September, 1954] K. N. RAMACHANDRAN AND P. R. YERI 161
wool is free from all moisture. The percentage of moisture content and the regain
is calculated in accordance to the following formula.
Percentage of moisture content= W1-W2/W1X 100
Percentage regain= W1-W2/W2X 100
where
W1 = Weight of the sample of wool before drying
W2 = Weight of the sample of wool after drying
DETERMINATION OP SCALES ON WOOL FIBRE
Wool, amongst all the other fibres of animal origin, has a marked felting quality.
This is attributed to the presence of scales on wool fibre, which facilitates the move-
ment of fibres towards their root end during the process of milling. Also the elastic
nature of wool fibres contributes towards this. The absence of scale structure on
wool fibre would not have produced the unshrinkable fabrics. In the process of
preparing non-felted fabrics, it is the destruction of scale structure by chemical
treatment of wool with chlorine that results in non-shrinkable finish for wool. Hence
an estimation of the number of scales per unit length of the fibre provides an indi-
cation of the felting quality of wool.
Procedure. The wool fibre is washed free of dirt and grease in distilled water
and benzene. It is then placed in between two layers of a thin thermoplastic film
and then sandwiched between two cover slips. This assembly is held between
a clamp, the jaws of which exert sufficient pressure on the film in contact with the
fibres. The whole assembly is left in an electric oven at 90°C. for 15 to 20 minutes.
The clamp is taken out, immediately disassembled and the fibre is removed with a
soft brush. The film on which the impressions of the fibre are transferred is fast-
ened to a microscopic slide by means of strips of transparent adhesive tape. The
slide with the impression of the film facing downwards is mounted on the WIRA
Projector. The number of scales per 100 microns are counted along the edge of
each fibre. Five such fibres for each type are taken for the determination of the
scales.
CRIMPS IN WOOL
Wool buyers are mainly guided by the number of crimps per inch when they
buy wool for processing fine counts of yarn. This is mainly due to the fact that the
crimps are correlated with the fineness of fibres. It is found that fine fibres have
more crimps per inch which are uniform and regular. Indian wools do not display
this character conspicuously though the undercoat of fine fibres exhibit waviness.
Sampling. About 1 gm. of sample is collected from each of the neck, wither,
shoulder, side, back and britch regions of the body of the sheep. The ½ gm. of sample
is spread so as to set its basal protion against a steel rule and two locks of 50 fibres
are randomly drawn and these when pooled together constitute the final sample.
162 METHODS OF ANALYSIS OF WOOL FIBRE [Vol. XXIV, Part III,
This process is repeated for each of the six regions so that crimps are estimated for
each of the six regions to obtain the within animal variation.
While sampling from a commercial bale, 1 lb. of wool is collected from the
different portions. This bulk shall be the result of eight pickings of approximate y
two ounces each. At each stage of halving, half is discarded at random till the
bulk of wool weighs only 0.5 gram. This sample is spread to six inches in length
and the basal portion is set against a steel rule on a black velvet board. Six draw
ings at random of about 50 fibres pooled together, shall constitute final sample.
Procedure. The sample is cleaned in benzene and dried between two pads of
filter papers. Each fibre is placed on a black velvet board, weighed down by a
microscopic slide against a steel rule. The number of crimps are counted
from end to end and the unstraightened length of the fibre is recorded. This proce
dure is repeated and the fibres in the entire sample are recorded for crimps, in the
case of the sample obtained from the animal or bale. Also the six different samples
obtained from the animal are analysed for crimps but the average of crimps are
calculated for each of the regions separately.
The average number of crimps per unit length is calculated according to the
following formula Σn/L/N
where
n is the number of crimps
L is the unstraightened length of the fibres
N is the total number of fibres
and
Σ denotes summation
ACKNOWLEDGMENT
The authors thank Dr. C. Nanjundayya, Ph. D. (Manch.), F.T.I., Director,
Technological Laboratory, Bombay, for going through the manuscript and
making useful suggestions.
SAURASHTRA WOOLS-THEIR PHYSICAL CHARACTERS
AND POSSIBILITIES FOR IMPROVEMENT*
By B. B. BUCH and GURUBAX SINGH MAHAL, Government Livestock Farm,
Hissar
(Received for publication on 19 August 1953)
I NDIA holds a unique position in the world wool trade for producing a high quality
of carpet wools. For this superior carpet quality of the wools, a fairly large
proportion of the total production in the country, goes in the international trade
which helps in earning a substantial amount of foreign currency every year. During
the year 1952, 18 million pounds of wool is reported to have been exported to the
U. S. A. alone [Anonymous, 1953] out of the total estimated production of 54.33
million pounds annually [Anonymous, 1948].
Although the total production of wool is in excess of the domestic requirements
of the country, India needs to import considerable quantity of fine wools for the
manufacture of clothings every year. This is because the indigenous wools are
only suited for carpet manufacture. To cut short imports and attain self sufficiency
in fine wool, concentrated efforts are necessary for the improvement of sheep types
in the country.
Before definite breeding programme is finalised towards the production of fine
quality wool, it is essential to carry out a proper survey of the existing sheep types
to study the potentialities of suitable breeds for such an improvement.
Of the various types of wools produced in the country, ' Joria ' wool has been
recognised as one of the most popular wools and is reported to being used for the
manufacture of tweeds, woollen pattis, flannels, etc. in the United Kingdom and
blankets, expensive tweeds, single shade clothings, carpets, etc. in the United
States [Anonymous, 1945]. Marketing Department of the Government of India has
classified 'Joria' wool as clothing wool [Anonymous, 1945]. The name 'Joria'
is given for the reason that the major quantity of the wool, from its origin, used to
be exported from the port of the same name. The wool actually is a mixture
of wools coming from different parts of Saurashtra State and adjoining areas of
Gujrat and Rajasthan.
Saurashtra State is the outcome of the amalgamation of several Western India
States into one unit after the achievement of Independence. The total popula-
tion is estimated at 4,000,000 people. This peninsula is formed by the extension
of the Arabian Sea on two sides forming two gulfs—Gulf of Cutch on the north-west
and the Gulf of Cambay on the south-east side. The natural barrier of the sea on
three sides has been responsible for maintaining the purity of sheep and whatever
foreign blood could come has infiltrated from the North Gujrat and Rajasthan
* This paper is based on the Research Problem submitted in partial fulfilment of the requirements
for the Post-Graduate Diploma course in Sheep Husbandry and Wool Production at the Government
Livestock Farm, Hissar. The course is run jointly by the Indian Council of Agricultural Research and
the Government of Punjab.
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