Now, in the Prologue to the "Canterbury Tales" we know that the observations could not have been recorded except at complete hours, because the construction of the metre will not admit the supposition of any parts of hours having been expressed.
We are also satisfied that there can be no mistake in the altitudes, because nothing can alter the facts, that an equality between the length of the shadow and the height of the substance can only subsist at an altitude of 45 degrees; or that an altitude of 29 degrees (more or less) is the nearest that will give the ratio of 11 to 6 between the shadow and its gnomon.
With these data we proceed to the following comparison:
| Forenoon altitude 45°. | Afternoon altitude 29°. | ||||
| Hour. | Declin. | Hour. | Declin. | ||
| XI | A.M. | 8° 9′ N. | II | P.M. | 3° 57′ S. |
| X | " | 13° 27′ " | III | " | 3° 16′ N. |
| IX | " | 22° 34′ " | IV | " | 13° 26′ " |
| VIII | " | Impossible. | V | " | Impossible. |
Here we immediately select "X A.M." and "IV P.M." as the only two items at all approaching to similarity; while, in these the approach is so near that they differ by only a single minute of a degree!
More conclusive evidence therefore could scarcely exist that these were the hours intended to be recorded by Chaucer, and that the sun's declination, designed by him, was somewhere about thirteen degrees and a half North.
Strictly speaking, this declination would more properly apply to the 17th of April, in Chaucer's time, than to the 18th; but since he does not profess to critical exactness, and since it is always better to adhere to written authority, when it is not grossly and obviously corrupt, such MSS. as name the 18th of April ought to be respected; but Tyrwhitt's "28th," which he states not only as the result of his own conjecture but as authorised by the "the best MSS.," ought to be scouted at once.
In the latest edition of the "Canterbury Tales" (a literal reprint from one of the Harl. MSS., for the Percy Society, under the supervision of Mr. Wright), the opening of the Prologue to "The Man of Lawes Tale" does not materially differ from Tyrwhitt's text, excepting in properly assigning the day of the journey to "the eightetene day of April;" and the confirmation of the forenoon altitude is as follows:
"And sawe wel that the schade of every tree