A new testing apparatus has been developed to investigate the characteristics of an air permeability of fabrics under high-speed air flows. Disccusions were made by using parameters A and B which were defined as special parameters of an air permeability in the previous papers. The result shows that the parameters A and B change in steps at about 4mmHg (30m/sec), where the parameter B showing the dimension of capilary portion decreases into very small value, and the parameter A showing the dimension of nozzle part definitely dominates. This phenomena can be considered that the air flow being laminar at a low air speed becomes turbulent at a high air speed over the critical Reynolds number. When an air flow increases to a higher value the fabric deformation occurs and at a certain point the parameter B appears again due to change of fabric structure, but the aspect shows that nozzle type phenomenon dominates and becomes stable again after the fabric deformation reaches constnat.
It is concluded that the air permeability of fabric at a high speed air flow is mainly explained by the parameter A, and can be considered as the nozzle type phenomena. The measured values by a Frazier permeometer prescribed in the Japanese Industrial Standard (JIS) shows only an air permeability at a given pressure and cannot express significant air permeability of fabrics in both low-and high-speed air flow. A and B are recommended as satisfactory parameters representing the air permeability at both highand low-speed air flow.

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The author obtained the following results from colour measurement of complained samples with colour unevenness:
(1) Errors of colour measurement in those samples were between 0.2ΔE (NBS unit) and 0.4ΔE (Adams-Nickerson-coefficient 40-unit) that were generally said to be an allowable limited value of colour difference.
(2) In those samples with colour unevenness the errors of colour measurement of woven fabrics were smaller than that obtained by yarns from woven fabrics samples.
(3) It was found that the errors of colour measurement of cotton yarns were larger than that of polyester 65/cotton 35 blended yarns.
(4) Moreover in those samples with colour unevenness it was also found that the colour difference between normal and abnormal parts in samples was almost recognized.

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