l'hotomicrographs are shown which confirm previous deductions that the effective ness of polymer treatments in reducing felting shrinkage of wool is rdated to the spreading of polymer over the surface of fibers. Chemical pretreatments which increase the critical surface tension of wool allow better spreading so that polymers are then deposited as thin surface films instead of in relatively large lumps as on normal wool. Only small amounts (1-2%; on the weight of wool) of polymer are therefore required when conditions for good spreading of polymer on wool are realized. Shrinkage-time curves of polymer-treated wool have the same shape as those of untreated wool and of wool made shrink-resistant by oxidative treatments. Polymer is not removed during the shrinkage tests. so that the actual mechanism of felting is probably the same in all cases.

The absorption of mercuric ions by wool is strongly inhibited by sodium chloride. Complex metal ammines are readily sorbed from ammonia solutions and then desorbed from wool by acid. A technique suitable for removing low concentrations of copper from nickel solutions is described.

The effects of boiling aqueous solutions on wool oxidised with a variety of reagents have been studied. Strength and weight losses for oxidised wool (as for untreated wool) were at a minimum at pH 3–. Wool that had been treated with hydrogen peroxide to oxidise about 7% cystine was damaged no more than untreated wool in the boiling solutions, but wool treated with shrink‐resist agents (acid chlorine, permonosulphuric acid–sulphite, permanganate–salt) was damaged more severely than untreated wool. This increased susceptibility to damage is probably due to attack by the shrink‐resist agents on the cuticle of the fibres and therefore is an inherent feature of wool made shrink‐resistant by oxidative treatments in aqueous solution. Investigations on the dyeing of shrink‐resistant wool with milling acid and 1:2 metal‐complex dyes are reported. Strength and weight losses were minimised by dyeing at pH near 4 in the presence of non‐ionic dyeing assistants and by keeping the temperature to which the bath was ultimately brought to the minimum required forexhaustion and thorough penetration of the dyes into the fibres, usually about 85–90°C.

The development of a simple pad‐bake pigment coloration method for untreated wool fabric is described. The process is intended particularly for colouring curtain fabrics of light and open construction.

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