《宋史·志·卷一》
有人说应当树立八尺的表，等待圭尺上八尺的日影在四十九天多，应当用四十九天五分作为临安冬至后初限，用它减去冬夏二至的初限，得出一百三十三天多作为夏至后初限。
或谓当立八尺之表，俟圭景上八尺之景在四十九日有奇，当用四十九日五分为临安冬至后初限，用减二至限，得一百三十三日有奇为夏至后初限。
Some people said that an eight-foot sign should be erected, and when the eight-foot shadow on the measuring rod was more than forty-nine days, it should be taken as the beginning of the winter solstice in Lin'an after forty-nine days and five minutes, and it should be subtracted. The first limit of the winter and summer solstices is obtained as more than 133 days as the first limit after the summer solstice.