The Structure of the Cotton Hair

From studies of the growing cotton plant in Egypt the author was led some years ago to the conclusions that the wall of the cotton-seed hair-cell was “probably composed of concentric layers, laid down during the active growth of each successive night, and numbering about twenty-five in all . . . they would thus, at the most, be about 0∙0004 mm. in depth, so that their resolution by the microscope is highly improbable without some previous treatment.” Various methods were tried with the intention of bringing these layers into the limits of microscopic vision, but it was not until five years later that an accidental observation gave the clue to a method by which the limitations of microscope observation may be extended, and these layers made actually visible. The observations which followed, demonstrating the existence of concentric layers in the wall of the cotton-hair as well as in the “fuzz-hairs,” would have been interesting in any case on account of their bearing on all the physical and chemical problems which this typical cellulose presents. C. F. Cross has insisted on the necessity for considering cellulose problems in terms of “the ultimate fibre," but it now seems probable that the ultimate unit components must be the single layers composing the wall of the said fibre. The bare fact of the existence of such layers would have had no particular significance if it could not have been connected with previous precise study of the growth of cotton-hairs. By counting the number of layers in material previously preserved at known dates during the course of those studies, and remembering the cardinal fact that growth is daily arrested by the sunshine effect under Egyptian conditions, we have been able clearly to show that these layers are actually the growth-rings whose existence we had ventured to postulate. Knowledge of their real existence must materially affect some of our views concerning the physical properties of such hairs.

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Soluble nucleotides in developing cotton hair

Phytochemistry ◽

10.1016/s0031-9422(00)85845-8 ◽

1969 ◽

Vol 8 (4) ◽

pp. 737-741 ◽

Cited By ~ 25

Author(s):

Gerhard Franz

Keyword(s):

Cotton Hair

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The Wall of the Cotton Hair

Nature ◽

10.1038/127742b0 ◽

1931 ◽

Vol 127 (3211) ◽

pp. 742-743 ◽

Cited By ~ 1

Author(s):

C. H. BROWN ◽

ABD EL GHAFFAR SELIM ◽

W. LAWRENCE BALLS

Keyword(s):

Cotton Hair

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Aerodynamic Drag of Cotton Fibers in Crossflow

Textile Research Journal ◽

10.1177/004051757704700512 ◽

1977 ◽

Vol 47 (5) ◽

pp. 381-386 ◽

Cited By ~ 4

Author(s):

R. A. Taylor

Keyword(s):

Aerodynamic Drag ◽

Fiber Surface ◽

Reynolds Numbers ◽

Circular Cylinders ◽

Cotton Fibers ◽

Number Range ◽

Fiber Fineness ◽

Aerodynamic Drag Coefficient ◽

Cotton Hair ◽

Flow Drag

“When a single cotton hair or fiber is exposed to a moving airstream, it experiences a fractional force induced by the relative movement of the air near the fiber surface. This force, known as aerodynamic drag, was measured for several cottons, each having a different Micronaire reading. Individual fibers were selected for fiber fineness and installed in a specially designed wind tunnel apparatus. Drag-force measurements for crossflow velocities from 12 to 280 cm/sec were recorded. Correlation of the test results show that aerodynamic drag coefficient for all cotton fibers can be expressed by the relation Cd = 10.35/Re0,825 for the 0.07 to 0.8 Reynolds number range, and Cd = 10.8/Re0,876 for the Reynolds numbers from 0.8 to 3. Laminar flow drag theories for smooth circular cylinders in crossflow are compared with the data recorded for cotton fibers.

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