Doyle's Rule

6 September 2011

Diana Curry sent the following puzzling observation:

“I have a copy of Scribner’s Log Table by Doyle’s Rules. I also have a spreadsheet where I enter a log’s length and diameter and calculate the board feet based on Doyle’s Rules. I’ve found that sometimes what is on the table is rounded and sometimes it is truncated. For example, if the length is 9’ and diameter is 21”, the formula comes up with 162.56 board feet. The table says 162, so it is truncating. However, if the length is 9’ and the diameter is 19”, the formula comes up with 126.56 board feet, and the table says 127, so it rounds. Is there any rule that specifies when the board feet should be rounded and when truncated?”

Can anyone account for the book's figures?

27 April 2005

Steve Jeffers informed us the calculator had stopped working.

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Last revised: 6 September 2011.