Rule regarding treatment of Mixtures (p.1)

When liquids or other substances composed of several ingredients which are subject to different rates of duty in accordance with the Tariff are imported so mixed that the Customs cannot readily ascertain the quantity and value of the component parts thereof, duty shall be charged on the whole at the highest of the rates applicable to the component parts, unless the mixture is already specifically provided for in the Tariff. 

Notes to Sections I, II, III, and IV (p.2)

In case Piece Goods or Knitted Tissues are constituted of more than one kind of fibre, the presence of any kind of fibre which does not exceed 5 per cent by weight shall not affect the tariff classification of such goods.

The classification of goods made of Cotton, Flax, Ramie, Hemp, Jute, Wool, and/or Silk (Natural or Artificial) shall not be affected by such goods having been stitched, taped, whipped or faced with materials other than those of which the goods are made. 

Articles consisting partly of lace, trimmings, or any other ornamental materials or decorated therewith are liable to a duty of 10 per cent ad valorem in addition to the ordinary duty leviable thereon. 

Note to Section IV

The term "Silk" in this Tariff includes Artificial Silk. The term "Artificial Silk" includes Rayon, Rayon Staple Fibre, and other Synthetic Textile Fibres. 

Union (Combination) Yarn made of Cotton or Wool and more than 5 per cent by weight of Artificial Silk (i.e., Rayon, Rayon Staple Fibre, and other Synthetic Textile Fibres) shall be classified as Spun Artificial Silk. Union (Combination) Yarn made of Cotton or Wool and 5 per cent or less by weight of Artificial Silk (i.e. Rayon, Rayon Staple Fibre, and other Synthetic Textile Fibres) shall be classified as Cotton or Woollen Yarn. 

Mixed (Blended) Yarn made of Cotton or Wool and 50 per cent or over by wieght of Artificial Woollen Yarn or non-lustrous Rayon Staple Fibre or other non-lustrous Synethtic Textile Fibres shall be classified as Artificial Woollen Yarn. Mixed (Blended) Yarn made of Cotton or Wool and less than 50 per cent by witgth of Artificial Woollen Yarn or non-lustrous Rayon Staple Fibre or other non-lustrous Synthetic Textile Fibres shall be classified as Cotton or Woollen Yarn.