Delta G conversion

[carbon]

JonGoku's reference to a temp conversion chart reminded me of something I've alwyas been a bit curious about. In Palmers 'How to brew' there is a conversion chart near the back of the book that lets you know how much to adjust your gravity readings for temperature. What has never made sense to me is this.. the chart lists different temperatures and says to add that much to your reading to compensate for temperature. I believe it is calibrated to 59° so that it has a delta G of 0. I would think that if the temperature were lower than 59° that you would need to subtract that amount from your reading to get an accurate number, and if it is above 59° that you would add that number. The chart only says to add to the reading. Has something been left out? Am i missing something? I don't have the book in front of me so I could be remembering incorrectly, but I don't think so.

[kevinham]

http://www.howtobrew.com/appendices/appendixA.html

It lists negative values to add if it is below 59F.