ROVING REQUIRED.
33. If you want to spin another number with same draught, write your number that you want to spin (as above) and divide that by the draught. That will give you hank roving required.
TO FIND DRAUGHT CHANGE GEAR.
34. Rule to find the draught change gear required. When you change from one number to another on a frame or mule, when the draught and roving both have to be changed, multiply the number of the yarn being spun by the hank roving desired, and that product by the number of teeth in the draught change gear; using that for a dividend. Then multiply the number of the yarn desired by the hank roving, using that for a divisor; that product divided will tell the draught change gear that is required.
TWIST GEAR.
35. The way I was taught to find the twist gear by square root of the number of yarn. Multiply the twist gear in use by the square root of the number being spun, and divide that product by the square root of the number you want to spin. That will give you the twist gear required.