Mary E. Hourihan

Comparison of Methods for Estimating Fiber Fineness

The Micronaire and Port-Ar airflow instruments are in use in this country for the determination of the average fiber diameter of wool fibers. The results from these instruments were compared with those from three laboratories which had determined the average fiber diameter on 90 wool top samples by the microprojection method. Results from the analysis of variance indicate that either instrument can be used equally well for determination of mean wool-fiber diameter.

Wool Top Analysis by an Electronic Fiber Fineness Instrument

A modified Electronic Fiber Fineness Instrument (EFFI) was used to obtain measurements of the average diameters and variability of 90 laboratory samples of wool tops produced from individual Rambouillet, Targhee, and Columbia fleeces and of three samples of commerciatly produced tops. The results were compared with results obtained by three laboratories which measured the same tops by the microprojection method. Least-squares procedures were utilized to test for differences between the methods, and the resulting data are presented along with correlations of results from the two methods. It is recognized that the EFFI gives slightly greater fiber-diameter readings and greater standard deviations than the short-fiber method. However, it seems that the EFFI can be used more speedily and conveniently and equally as well as the microprojection method for the measurement of fiber diameter and relative placement of samples according to diameter.