Critical Note 26.
§4, l. 16.  For `25 degrees', all the MSS. have `15 degrees'.  The mistake is probably Chaucer's own; the correction was made by Mr. Brae, who remarks that it is a mere translation from the Latin version of Ptolemy's Tetrabiblos, which  has -- `Signum ascendentis, quod est a quinque gradibus qui super horizontem ante ipsum ascenderant usque ad viginti quinque qui ad ascendentem remanserint'; Lib. iii. c. 10.  In fact, it is clear that 25 must be added to 5 to make up the extent of a `house', which was 30 degrees.