This document specifies a method, by determining the nitrogen content, to calculate the proportion of each component, after the removal of non-fibrous matter, in textiles made of mixtures of jute with animal fibres. The animal-fibre component may consist solely of hair or wool, or of any mixtures of the two. This part of ISO 1833 is not applicable to products in which dyestuffs or finishes contain nitrogen. NOTE Because this method differs in principle from the general method based on selective solubility set out in ISO 1833-1, it is given in a form that is complete in itself.