Part 18 (1/2)
373 Rope-fibres from Grenada.
(b) 398 Report of Experiments on Indian Jute (1).
435} Fifth and Sixth Report on Australian Fibres.
473} 1896. 68 Hibiscus and Abroma Fibres.
104-5 Hibiscus, Urena, and Crotalaria Fibres.
141 Indian Sisal (c) 182-3 Report of Experiments on Indian Jute (2).
264 Sanseviera from a.s.sam.
From the above we may draw the general conclusion that the scheme of investigation has been found in practice to answer its main purpose, viz. to afford such numerical constants as determine industrial values.
In ill.u.s.tration we may cite (a) the results of a.n.a.lyses of specially selected samples of jute, from which it will be seen that there is a close concordance of value as ordinarily determined from external appearance, with the chemical constants as determined in the laboratory.
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Quality of Jute
____________________________
_____________________________________
Low
Medium
Extra
Extra Fine
____________________________
_______
________
_______
____________
Moisture
11.0
10.4
11.1
9.6
Ash
0.87
2.8
1.0
0.7
Alkaline hydrolysis (a)
5 mins. boiling
13.2
11.6
8.5
9.1
Alkaline hydrolysis (b)
60 mins. boiling
16.1
17.5
12.5
13.1
Mercerising treatment
9.2
10.5
10.3
8.5
Nitration (increase p.ct.)
36.6
35.7
37.5
36.7
Cellulose (yield)
71.4
70.0
79.0
77.7
Acid purification
2.6
1.3
1.9
2.0
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________
_______
____________
A useful series of experiments, initiated by the Inst.i.tute, is that noted under (b) and (c) above.
(1) To ascertain the quality of the fibre extracted from the plant at different stages of growth, quant.i.ties of 400 lbs. of the stalks were cut at successive stages and the fibre isolated after steeping 14-20 days. The fibre was s.h.i.+pped to England and chemically investigated, with the following results:
No. 1. Cut before appearance of inflorescence.
” 2. ” after budding.
” 3. ” in flower.
” 4. ” after appearance of seed-pod.
” 5. ” when fully matured.
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(1)
(2)
(3)
(4)
(5)
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_______
_______
______
______
_______
Moisture
11.55
8.74
10.7
10.0
9.72
Ash
1.1
1.1
1.1
1.1
0.90
Alkaline hydrolysis (a)
6.2
8.5
9.7
8.9
7.3
” ” (b)
10.5
11.9
11.6
12.0
11.2
Mercerising treatment
10.2
10.7
12.0
8.1
11.0
Nitration
37.2
32.1
32.2
33.2
36.6
Cellulose
74.0
76.2
74.1
74.8
76.4
Acid purification
0.8
0.5
0.7
2.4
1.4
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_______
______
______
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It will be thus seen that there are no changes of any essential kind in the chemical composition of the bast fibre throughout the life-history of the plant, confirming the conclusion that the 'incrustation' view of lignification is consistent only with the structural features of the changes, and so far as it has a.s.sumed the gradual overlaying of a cellulose fibre with the lignone substance it is not in accordance with the facts.
Examination of the samples from the point of view of textile quality showed a superiority of No. 1 in fineness, softness, and strength; from this stage there is observed a progressive deterioration, but the No. 4 sample (which was taken at the usual period of cutting) is superior to No. 5.
In a further series of experiments (c) the jute was subjected to certain chemical treatments immediately after the separation of the fibre from the plant. These consisted in steeping (1) in solution of sodium carbonate, as well as of plant ashes, and (2) in sulphite of soda, the purpose of the treatments being to modify or arrest the changes which take place in the fibre when press-packed in bales for s.h.i.+pment. The samples were s.h.i.+pped from India under the usual conditions and examined soon after arrival. It was found that the chemical treatments had produced but small changes in chemical composition of the fibre-substance. The sulphite treatment was the more marked in influence, somewhat lowering the cellulose and nitration constants. The conclusion drawn from the results was that they afford no prospect of any useful modification, i.e. improvement of the textile quality of the fibre by any chemical treatments such as could be applied to the fibre on the spot before drying for press-packing and s.h.i.+pment.
The other matters investigated in the Inst.i.tute laboratory and reported on as indicated above are rather of commercial significance, and contributed no points of moment to the chemistry of cellulose.
OBSERVATIONS ON SOME OF THE CHEMICAL SUBSTANCES IN THE TRUNKS OF TREES.
F. H. STORER (Bull. Bussey Inst., 1897, 386).
(p. 172) An examination of the outer and inner wood and of the bark of the grey birch, at different seasons of the year, gave the following yields of furfural p.ct. on the dry substance:
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Wood
_______________
Bark
Inner
Outer
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_______
_______
______
May