I wonder how much time my great-grandfather spent making calculations like these, below? Do you suppose this method is still used for weighing cattle ;)?
Miscellaneous Rules. (page 122)
Rules for Ascertaining the Number of Tons of Hay in a Stack. – Measure around the stack in the largest place, multiply the number of feet by one-third of the height, point off the two right hand figures, and you have the number of tons in the stack.
To Find the Number of Tons of Well Pressed Hay in a Mow. – Measure the number of yards the bay is long, and the number of yards the bay is wide, multiply the two together; that product multiplied by the number of yards the bay is deep, and divided by 15, will give the number of tons the mow contains.
Rule for Measuring Grain in Bins. – Multiply the length of the bin by the width of the bin, and that product by the depth of the bin, and multiply that amount by 4, and divide that product by 5, and you have the number of bushels the bin contains.
To Determine the Price per load of Hay. – Multiply the weight by one-half the price per ton, point off the three right hand figures, the figures at the left will be the amount in dollars and cents that the load comes to.
Weight of Cattle. – To find the approximate weight measure as follows: 1st, the girth behind the shoulders, 2nd, the length from the forepart of the shoulder-blade along the back to the bone at the tail, in a vertical line with the buttocks. Then multiply the square of the girth in feet, by 5 times the length in feet. Divide the product by 15 for average cattle, if cattle be very fat by 1.425, if very lean by 1.575; and the quotient will be the dressed weight of the quarters. Thus, the girth of a steer is 65 feet, and the length from the shoulder-blade to the tail bone is 5.25. The square of 65 is 42.25 and 5 times 5.25 is 26.25. The square of 65 is 42.25 and 5 times 5.25 is 26.25. Multiplying those together gives 1109.0625, which, when divided by 15 produces 739.375 lbs the approximate net weight of the steer after being dressed.