34
26
87
78
9
One of the most useful purposes to which a knowledge of this principle can be put is in changing the weave of a fabric, to find the threads per inch of a given count of yarn required to keep the same firmness as in a sample cloth.
It must be remembered that the word “firmness” is here used as implying that the space between the threads bears the same relation to the diameters of the threads in both cases, or, if the given cloth is perfect, the proposed one will also be perfect.
Suppose it is desired to make a “two and two” twill of the same “firmness” as a plain cloth made with 103 threads per inch.
The yarns being the same, the number of threads per inch required will be as the ends plus intersections in a given number of ends in both patterns.