and √11292 = 106½ ∴ picks per inch required = 106½
One advantage gained by a knowledge of the principle of cloth “balance” is that the number of picks per inch which a given pattern or weave will take can easily be obtained by calculation. This is of great advantage to designers for Jacquard weaving, as it often occurs that a design is made and the cards cut for a pattern which will not admit of the required number of picks of the given counts being put in the cloth, which a slight alteration in the ground weave would have rendered possible.
To alter the Weight.—If the weight of a cloth is required to be altered, and the same firmness kept, the threads per inch and counts can be found on the same principle.
If a cloth is made heavier it must be done by using coarser yarns and fewer threads; it cannot be done by using more threads, and preserve the same “firmness” or “perfection.”
Suppose a sample piece of cloth weighing 10 lbs. is made with 93 threads of 45’s, and it is proposed to make a piece of the same length and width, but weighing 15 lbs. To find the threads per inch and counts of yarn to keep the same firmness.
The weights of two cloths will vary as the square roots of the counts if they are of the same perfection.
Therefore—
Weight of
proposed cloth.
Weight of
sample.
As 15 lbs.