28 TlMEHRI. 
materials for industry according to their application, and 
these groupings, it seems, follow their classification 
based on origin, strufture, and chemical composition. 
Cotton, which consists of independent ultimate cells, 
differs from raw materials which are "fibre-aggregates", 
or bundles of ultimate fibres bound together by conta6t 
or adhesion of the cell-walls, or cemented by a third 
substance. In the cases of straw and Esparto grass, the 
whole plant is regarded as a fibrous raw material. 
A certain unit of length is required in spinning pro- 
cesses, and the value of a raw material depends on the 
length, fineness, or divisibility of the fibre bundles of 
which it is composed. Strength and durability are also 
qualities which determine its value, and these depend 
upon the ultimate strufture and chemical composition — 
ascertained by laboratory investigation. 
That ptfrtion of raw fibre material which resists the 
ordinary agents and alkaline solvents used in bleaching, 
is the cellular basis of the material, consisting of ultimate 
fibres or fibre cells, which vary in length according to 
the plant source from which they are derived. The 
lengths of these individual cells with their proportion in 
weight to the raw fibre, are taken as tests of value — 
" Constants, " as they are technically termed. 
Flax, hemp, rhea and jute, which are the fibres of 
dicotyledonous plants, possess a percentage of cellulose 
varying only from 75 to 80 degrees, while the length of 
ultimate fibre, which in flax is set down at 25-40 mm. 
and in jute at 3m. rises to 60-200 mm. in rhea ; and in 
monocotyledonous plants, furnishing a large proportion 
of rope-material such as manilla (Musa) or plantain, New 
Zealand flax (Phormium) and Agave, cellulose is from 
