SECTIONAL TRANSACTIONS.— TEXTILES. 415 



(wool), colour, horns, length of ears and of tail, and other less denned characters — 

 sometimes probably linked together — may now often be treated as characters subject 

 to normal Mendelian inheritance and, consequently, by suitable breeding procedure, 

 a most useful adjustment of race to environment ensured. 



Mr. J. B. Speakman. — The Intracellular Structure of the Wool Fibre. 



The gel structure of the wool fibre has found elucidation through a study of the 

 stress-strain relationships of single fibres under varying rates of loading at various 

 temperatures and humidities. 



The relative positions of the constituent cells remain unchanged during the 

 extension of single fibres so that the behaviour of the fibre as a whole is that of the 

 single cell. The fibrillar structure within this cell is not arranged haphazardly, for 

 the extension-load curves show a sharp bend towards the load axis at 30 per cent. 

 extensions with finite rates of loading. There is, therefore, a tendency for the fibrilke 

 to lie along the axis of the fibre. 



Fibres extended in water at 18° C. remain perfectly elastic even up to 70 per cent, 

 extension, but such once-extended fibres are permanently more extensible at low 

 tension. The point of incidence of permanent alteration of single fibres depends on 

 the rate of loading, a fact which suggests plastic flow of fibrillse under stress. This 

 hypothesis has been confirmed in several independent ways. The permanent 

 alteration of wool fibres by extension is due, therefore, to the rupture and plastic 

 flow of fibrillar. Perfect recovery is governed by the elastic cell wall and elastic 

 fibrillae ; these draw back those fibrilbe which have taken permanent set and cause 

 them to fold up within the cell. 



Increasing humidity at constant temperature and increasing temperature at 

 constant humidity both produce increased solvation of the wool substance. With 

 increasing solvation, more and more fibrillee become capable of showing plastic flow 

 until the fibre as a whole is able to acquire permanent set. If extended wool fibres 

 are cooled in the stretched position after immersion in water at a temperature above 

 60° C, they fail to return to their original length. The permanent set realised in this 

 way is not due to a solution and redeposition of fibrilla?, but to plastic flow of all 

 parts of the constituent cells, including the cell wall. Re-immersion of the released 

 fibres in hot water invariably causes contraction. Even at 100° C. this contraction 

 occurs to a marked degree, but the return to the original length is incomplete. In all 

 cases contraction is due to a species of recrystallisation within the fibrillm. 



A comparative study of different wools, mohair, and human hair, showed that they 

 differ considerably in plasticity. These differences have been measured and serve to 

 explain the ease of manufacture of yarns and fabrics from merino as opposed to the 

 coarser crossbred wools. The elastic strains imposed on fibres during manufacture 

 are readily converted to plastic flow in the case of merino wools, whereas they persist 

 in the case of crossbred wools, making them more wiry and difficult to control. The 

 ability of wool fibres to dissipate elastic forces by plastic flow at constant length in the 

 way here described has not hitherto been contemplated. 



Monday, September 5. 



Dr. T. Oliver. — Predetermination of Wool Cloth Prices. 



Predetermination of cloth price must be based upon reliable costs. To fix a price 

 on the basis that our competitors are likely to quote a certain figure is out of date. 

 Without true costs the stability of a business must be uncertain. A manufacturer, 

 with sound costing system, will never be afraid to quote a bed-rock price. Lowest 

 cost per yard is no longer associated with lowest wages. A satisfied worker has a 

 high economic value. Although estimates of cost cannot be absolutely exact, yet 

 past experience will enable us to predetermine cost within narrow limits of error. 

 A price-fixing system should be simple, net burdened with detail. Convenient to 

 divide costs into (a) inanimate materials, (l>) animate labour, (c ) dead charges. Costs 

 of materials and piece-work are easily ascertained. Manufacturing charges vary as 

 <1) weight, (2) sett, (3) length, (4) value. 



Initial processes (sorting, scouring, carbonising, dyeing, teazing, scribbling, comb- 

 ing) and wool oil entail pure weight charges ; condensing, mixed weight-length 

 charge ; spinning -twisting introduce pure length variables. 



