IDENTIFICATION OF FIBERS. 



357 



different kinds of wood are employed not mentioned in the following- 

 table, such as poplar, which in some parts of the country is the common 

 name of species of Populus, but in ISTew York and elsewhere is often 

 applied to the Liriodendron tulipifera, also known as whitewood, while 

 the Tilia americana goes under the name of basswood. As all woody 

 fibers are more or less lignified, they give the yellow reactions of the 

 Dicotyledons with the linden and willow as in the table following. 



The reaction between iodin and sulphuric acid is sometimes a little 

 slow and the color is temporary, only lasting a few hours. Bent or 

 creased fibers color deeply in the flexures, and striae, either longitudi- 

 nal or radial in sections, will show more plainly as the coloration pro- 

 gresses. In many of the coarser fibers particularly, pieces of paren- 

 chyma will be seen that always color yellow, and may readily be known 

 by their irregular shape. 



Most of the fiber cells used in the textile industries, such as flax and 

 hemp, are parts of the inner layer or bark of Dicotyledonous plants 

 often known as bast cells. 



In Monocotyledons the fiber cells are often scattered irregularly 

 through the stem, and are white, coarse, light, and often brittle. (See 

 Study of Fibers, in the Introduction.) There are, however, many excep- 

 tions to the latter statement, especially among the palms, which are 

 Monocotyledons. The blue reaction in this class is not so definite as in 

 the other classes, quite a proportion of the cells of alfa or esparto turning 

 yellow, there being apparently two kinds of cells in this plant, which 

 are not mixed indiscriminately in the stem, but form separate layers, 

 each of which maintains its characteristic reaction, but becomes inter- 

 mixed in processes of manufacture. - The following table is a summary 

 of the distinguishing characters of the principal vegetable fibers. The 

 mean length and diameter are derived from a comparison of many 

 measurements, and hence do not in all cases represent the mean of the 

 extremes given 



Table C. — Synoptical table for the determination of fibers of vegetable origin. 



[All measures in millimeters. The reactions are understood to be with iodin and 



sulphuric acid.] 



DICOTYLEDONS GIVING BLUE KEACTION". 





Botanical name. 



Length of fiber Diameter of 

 cells. fiber cells. 





Common name. 



03 



C 



a 



Longest. 

 Smallest. 



i 



+3 



05 



Hi 



Remarks. 



Elax 



Linum usitatissimum. . . 



Cannabis sativa 



Hamulus lnpulus 



Urticasp 



Boehnierisi nivea 



Broussonetiapapyrifera 

 Crotalaria juncea 



Cytisus scoparius 



4 

 5 

 4 

 4 

 60 



I 



2 

 5 

 5 

 10 



So 



25 



10 



27 



120 



15 



7.8 



6 

 10 

 10 

 25 



66 0. 150 

 55 Olfi 



0.022 

 .022 

 .016 

 .05 

 .08 

 .030 



0.037 

 .050 

 .018 



.07 



'"035 



Cavity fine, yellow line. 



Hop 



19 

 55 

 200 

 25 

 12 



9 

 16 

 18 

 40 



.012 



.02 

 .05 

 .025 





Xettle . 





China grass 



Paper mulberry . 



Canal scarcely appar- 

 ent. 

 Yellow envelope. 



















Melilot ! Melilotns'alba 









Cavity large. 



Cotton 





















