s. 9. A TREATISE ON THE ASTROLABE. Previously edited by me for the Early English Text Society's Extra Series, in 1872; when I discovered that none but inferior MSS. had ever been previously printed, and that all other editions are, in various ways, incomplete. The only one of any worth is the modern edition by Mr. Brae, who was an excellent astronomer; but he unfortunately based his edition upon an 'edited' MS., written about 1555, which is not, after all, of a good type. The extraordinary errors in the early editions of the Astrolabe are well illustrated by Mr. Brae. For example, the statement in Part II. s. 6. l. 8 (vol. iii. p. 194) that 'the nadir of the sonne is thilke degree that is opposit to the degree of the sonne, _in the seventhe signe_,' appears in most early editions as 'in the 320 signe.' But 320 signs for the zodiac is much too liberal an allowance. My edition for the E.E.T.S. also contains an edition of Messahala's Latin treatise, from which Chaucer derived about two-thirds of his work; see vol. iii. p. lxx. This Treatise is of more importance than might be supposed, owing to Chaucer's frequent allusions to astronomical subjects. Every editor of Chaucer should know that there are nine spheres; otherwise, he may fall (as three editors have done) into the trap prepared by the scribe of the Harleian MS., who gives lines 1280 and 1283 of Group F of the Canterbury Tales in this extraordinary form:-- 'And by his _thre speeres_ in his worching' ... 'That in the _fourthe speere_ considred is.' It was a special pleasure to find that Chaucer's star Aldiran (Cant. Tales, F 265) was one of the stars marked on the 'Rete' or web of a Parisian astrolabe in A.D. 1223, and is described (in MS. Ii. 3. 3, in the Camb. Univ. Library) as being 'in fronte Leonis.' See vol. v. p. 380. Some attempts have been made to calculate the date of the Canterbury Tales from ll. 10, 11 of the Parson's Prologue. The absurdity of such an endeavour is patent to any one who knows enough of the old astronomy and astrology to be aware that the 'moon's exaltation' is merely a name for a sign of the zodiac, and has nothing whatever to do with the position of the moon itself. Here, again, the scribe of the Harleian MS. has turned the phrase _I mene_ into _In mena_[7], misleading many enquirers who fail to realise that he was as careless in this passage as in the former one. s. 10. THE CANTERBURY TALES. The great gain in this poem has been the foundation of the text upon the basis of the Ellesmere MS., the most satisfactory of all existing MSS. having any reference to Chaucer. The general excellence and correctness of its spellings and readings render it the safest on which to found rules for our guidance as to pronunciation, syntax, and prosody. For further remarks, see the Introduction to vol. iv. p. xvii.