Treatise on The Astrolabe : addressed to his son Lowys / by Geoffrey Chaucer ; edited from the earliest MSS. by Walter W. Skeat

Tractatus de Conclusionibus Astrolabii.

[Bred and mylk for childeren.]

[folio 1]

LItell Lowys my sone, I haue perceiued well by certeyne euidences thine abilite to lerne sciencez touchinge noumbres & proporciouns; ¶ & as wel considere I thy bisi preyere in special to lerne the tretis of the astrelabie. ¶ than, for as mechel as a philosofre seith, ¶ he wrappeth him in his frend, þat condescendith to the rihtful preiers of his frend / ther-for haue I geuen the a suffisaunt astralabie as for owre orizonte, compowned after the latitude of Oxenford / vp-on which, by mediacion of this litel tretis, I purpose to teche the a certein nombre of conclusions apertenyng to the same instrument. ¶ I seye a certein of couclusiouns, for thre causes. ¶ the furste cause is this: ¶ truste wel þat alle the conclusiouns that han ben fownde, or elles possibli myhten be fownde in so noble an instrument as an astralabie, ben vn-knowe perfitly to any mortal man in this regioun, as I suppose. ¶ a-nother cause is this ; þat sothly, in any tretis of the astrelabie þat I haue seyn, there ben some conclusions þat wole nat in alle thinges performen hir byhestes;

¶ & some of hem ben to harde to thy tendre age of .x. yer to conseyue. ¶ this tretis, diuided in 5 parties, wole I shewe the vnder ful lihte rewles & naked wordes in englissh ; for latyn ne kanstow yit but smal, my lite sone. ¶ but natheles, suffise to the thise trewe conclusiouns in englissh, as wel as suffisith to thise noble clerkes grekes thise same conclusiouns in grek, ¶ & to arabiens in arabik, ¶ & to Iewes in Ebrew, & to the latyn folk in latyn / whiche latyn folk han hem furst owt of othre diuerse langages, & writen in hir owne tonge, þat is to sein, in latyn. ¶ & god wot, þat in alle this[e] langages, & in many mo, han thise conclusiouns ben suffisantly lerned & tawht / & yit by diuerse rewles, ryht as diuerse pathes leden diuerse folk the rihte wey to Roome. ¶ Now wol I prey mekly euery discret persone þat redith or herith this litel tretis, to haue my rewde endytyng for excused, & my superfluite of wordes, for two causes. ¶ the firste cause is, for that curio[u]s enditing & hard sentence Is ful heuy atones for swich a child to lerne. ¶ & the seconde cause is this, þat sothly me semeth betre to writen vn-to a child twies a good sentence, than he for-get it ones. ¶ And lowis, ȝif so be þat I shewe the in my lihte Englissh as trewe conclusiouns touching this matere, & nawht only as trewe but as many & as subtil conclusiouns as ben shewed in latyn [folio 1b] in ani commune tretis of the astrelabie / kon me the more thank ; ¶ and preye god saue the kyng, þat is lord of this langage, & alle that him feyth bereth & obeieth, euerech in his degree, the more and the lasse. ¶ but considere wel, that I ne vsurpe nat to haue fownde this werk of my labour or of myn engin. ¶ I nam but a lewd compilatour of the labour of olde Astrolog[i]ens, and haue hit translated in myn englissh only for thi doctrine ; ¶ & with this swerd shal I slen envie.

¶ The firste partie of this tretis shal reherse the figures & the membres of thin Astrolabie, by-cause þat thow shalt han the grettre knowyng of thin owne instrument.

¶ The second partie shal teche the werken the verrey practik of the forseide conclusiouns, as ferforth & as narwe as may be shewyd in so smal an instrument portatif a-boute. ¶ For wel wot euery astrologien þat smalest fraccions ne wol nat ben shewid in so smal an instrument, as in subtil tables calkuled for a kawse.

¶ The .3. partie shal contienen diuerse tables of longitudes & latitudes of sterres fixe for the Astrolabie, ¶ & tables of declinacions of the [sonne], & tables of longitudes of Citeez & of townes ; ¶ & as wel for the gouernance of a clokke as for to fynde the altitude Meridian / & many [a]-nother notable conclusioun, aftur the kalendres of the reuerent clerk[e]s, frere I. Somer & frere N. Lenne.

¶ The .4. partie shal ben a theorik to declare the Moeuynge of the celestial bodies with [þe] causes. ¶ the whiche 4 partie in special shal shewen a table of the verray Moeuyng of the Mone from howre to howre, euery day [folio 2] & in euery signe, after thin Almenak / vp-on wych table ther folwith a canon, suffisant to teche as wel the maner of the wyrkyng of þat same conclusioun / as to knowe in owre orizonte with wych degree of the zodiac that the Mone arisith in any latitude / & the arising of any planete aftur his latitude fro the Ecliptik lyne.

¶ The .5. partie shal ben an introductorie aftur the statutz of owre doctours, in which thow maist lerne a gret part of the general rewles of theorik in Astrologie. ¶ in which .5. partie shaltow fynde tables of equacions of howses aftur þe latitude of Oxenford; ¶ & tables of dignetes of planetes / & other noteful thingez / yif god wol vouche sauf & his modur the mayde, mo than I be-hete, &c.