Astronomical Lore in Chaucer Part 8

Chaucer had too keen a sense of humor, too sympathetic an outlook on life not to see the irony in the ceaseless spectacle of mankind das.h.i.+ng itself against the relentless wall of circ.u.mstances, fate, or what you will, in undying hope of attaining the unattainable. He saw the humor in this maelstrom of human endeavor--and he saw the tragedy too. The _Knightes Tale_ presents largely, I think, the humorous side of it, _Troilus and Criseyde_, the tragic, although there is some tragedy in the _Knightes Tale_ and some comedy in _Troilus_.

It was fate that Troilus should love Criseyde, that he should win her love for a time, and that in the end he should be deserted by her. From the very first line of the poem we know that he is doomed to sorrow:

"The double sorwe of Troilus to tellen, That was the king Priamus sone of Troye, In lovinge, how his aventures fellen Fro we to wele, and after out of Ioye, My purpos is, er that I parte fro ye."[186]

The tragedy of Troilus is also the tragedy of Criseyde, for even at the moment of forsaking Troilus for Diomede she is deeply unhappy over her unfaithfulness; but circ.u.mstance is as much to blame as her own yielding nature, for Troilus' fate is bound up with the inexorable doom of Troy, and she could not return to him if she would.

There is no doubt that Chaucer feels the tragedy of the story as he writes. In his proem to the first book he invokes one of the furies to aid him in his task:

"Thesiphone, thou help me for tendyte Thise woful vers, that wepen as I wryte!"[187]

Throughout the poem he disclaims responsibility for what he narrates, saying that he is simply following his author and that, once begun, somehow he must keep on. In the proem to the second book he says:

"Wherefore I nil have neither thank ne blame Of al this werk, but pray you mekely, Disblameth me, if any word be lame, For as myn auctor seyde, so seye I."[188]

and concludes the proem with the words,--

"but sin I have begonne, Myn auctor shal I folwen, if I conne."[189]

When Fortune turns her face away from Troilus, and Chaucer must tell of the loss of Criseyde his heart bleeds and his pen trembles with dread of what he must write:

"But al to litel, weylawey the whyle, Lasteth swich Ioye, y-thonked be Fortune!

That semeth trewest, whan she wol bygyle, And can to foles so hir song entune, That she hem hent and blent, traytour comune; And whan a wight is from hir wheel y-throwe, Than laugheth she, and maketh him the mowe.

From Troilus she gan hir brighte face Awey to wrythe, and took of him non hede, But caste him clene oute of his lady grace, And on hir wheel she sette up Diomede; For which right now myn herte ginneth blede, And now my penne, allas! with which I wryte, Quaketh for drede of that I moot endyte."[190]

Chaucer tells of Criseyde's faithlessness reluctantly, reminding the reader often that so the story has it:

"And after this the story telleth us, That she him yaf the faire baye stede, The which she ones wan of Troilus; And eek a broche (and that was litel nede) That Troilus was, she yaf this Diomede.

And eek, the bet from sorwe him to releve, She made him were a pencel of hir sleve.

I finde eek in the stories elles-where, Whan through the body hurt was Diomede Of Troilus, tho weep she many a tere, Whan that she saugh his wyde woundes blede; And that he took to kepen him good hede, And for to hele him of his sorwes smerte, Men seyn, I not, that she yaf him hir herte."[191]

And in the end for very pity he tries to excuse her:

"Ne me ne list this sely womman chyde Ferther than the story wol devyse, Hir name, allas! is publisshed so wyde, That for hir gilt it oughte y-now suffyse.

And if I mighte excuse hir any wyse, For she so sory was for hir untrouthe, Y-wis, I wolde excuse hir yet for routhe."[192]

We have said that Chaucer's att.i.tude toward the philosophical aspects of astrology is hard to determine because in most of his poems he takes an impersonal ironic point of view towards the actions he describes or the ideas he presents. His att.i.tude toward the idea of destiny is not so hard to determine. Fortune, the executrix of the fates through the influence of the heavens rules men's lives; they are the herdsmen, we are their flocks:

"But O, Fortune, executrice of wierdes, O influences of thise hevenes hye!

Soth is, that, under G.o.d, ye ben our hierdes, Though to us bestes been the causes wrye."[193]

Perhaps Chaucer did not mean this literally. But one is tempted to think that he, like Dante, thought of the heavenly bodies in their spheres as the ministers and instruments of a Providence that had foreseen and ordained all things.

APPENDIX

I. Most of the terms at present used to describe the movements of the heavenly bodies were used in Chaucer's time and occur very frequently in his writings. The significance of Chaucer's references will then be perfectly clear, if we keep in mind that the modern astronomer's description of the _apparent_ movements of the star-sphere and of the heavenly bodies individually would have been to Chaucer a description of _real_ movements.

When we look up into the sky on a clear night the stars and planets appear to be a host of bright dots on the concave surface, unimaginably distant, of a vast hollow sphere at the canter of which we seem to be. Astronomers call this expanse of the heavens with its myriad bright stars the _celestial sphere_ or the _star sphere_, and have imagined upon its surface various systems of circles. In descriptions of the earth's relation to the celestial sphere it is customary to disregard altogether the earth's diameter which is comparatively infinitesimal.

If we stand on a high spot in the open country and look about us in all directions the earth seems to meet the sky in a circle which we call the _terrestrial horizon_. Now if we imagine a plane pa.s.sing through the center of the earth and parallel to the plane in which the terrestrial horizon lies, and if we imagine this plane through the earth's center extended outward in all directions to an infinite distance, it would cut the celestial sphere in a great circle which astronomers call the _celestial horizon_. On the celestial horizon are the north, east, south and west points. The plane of the celestial horizon is, of course, different for different positions of the observer on the earth.

If we watch the sky for some time, or make several observations on the same night, we notice, by observing the changing positions of the constellations, that the stars move very slowly across the blue dome above us. The stars that rise due east of us do not, in crossing the dome of the sky, pa.s.s directly over our heads but, from the moment that we first see them, curve some distance to the south, and, after pa.s.sing their highest point in the heavens, turn toward the north and set due west. A star rising due east appears to move more rapidly than one rising some distance to the north or south of the east point, because it crosses a higher point in the heavens and has, therefore, a greater distance to traverse in the same length of time. When we observe the stars in the northern sky, we discover that many of them never set but seem to be moving around an apparently fixed point at somewhat more than an angle of 40[194] above the northern horizon and very near the north star. These are called _circ.u.m-polar stars_. The whole celestial sphere, in other words, appears to be revolving about an imaginary axis pa.s.sing through this fixed point, which is called the _north pole_ of the heavens, through the center of the earth and through an invisible pole (the south pole of the heavens) exactly opposite the visible one. This apparent revolution of the whole star sphere, as we know, is caused by the earth's rotation on its axis once every twenty-four hours from west to east. Chaucer and his contemporaries believed it to be the actual revolution of the nine spheres from east to west about the earth as a center.

[Ill.u.s.tration: Fig. 1.]

For determining accurately the position of stars on the celestial sphere astronomers make use of various circles which can be made clear by a few simple diagrams. In Figure 1, the observer is imagined to be at O. Then the circle NESW is the celestial horizon, which we have described above.

Z, the point immediately above the observer is called the _zenith_, and Z', the point immediately underneath, as indicated by a plumb line at rest, is the _nadir_. The line POP' is the imaginary axis about which the star-sphere appears to revolve, and P and P' are the poles of the heavens.

The north pole P is elevated, for our lat.i.tude, at an angle of approximately 40 from the north point on the horizon. PP' is called the _polar axis_ and it is evident that the earth's axis extended infinitely would coincide with this axis of the heavens.

In measuring positions of stars with reference to the horizon astronomers use the following circles: Any great circle of the celestial sphere whose plane pa.s.ses through the zenith and nadir is called a _vertical circle_.

The verticle circle SPNZ', pa.s.sing through the poles and meeting the horizon in the north and south points, N and S, is called the _meridian circle_, because the sun is on this circle at true mid-day. The _meridian_ is the plane in which this circle lies. The vertical circle, EZ'WZ, whose plane is at right angles to the meridian, is called the _prime vertical_ and it intersects the horizon at the east and west points, E and W. These circles, and the measurements of positions of heavenly bodies which involve their use, were all employed in Chaucer's time and are referred to in his writings.[195]

The distance of a star from the horizon, measured on a vertical circle, toward the zenith is called the star's _alt.i.tude_. A star reaches its greatest alt.i.tude when on the part of the meridional circle between the south point of the horizon, S, and the north pole, P. A star seen between the north pole and the north point on the horizon, that is, on the arc PN, must obviously be a _circ.u.m-polar star_ and would have its highest alt.i.tude when between the pole and the zenith, or on the arc PZ. When a star reaches the meridian in its course across the celestial sphere it is said to _culminate_ or reach its _culmination_. The highest alt.i.tude of any star would therefore be represented by the arc of the meridional circle between the star and the south point of the horizon. This is called the star's _meridian alt.i.tude_.

The _azimuth_ of a star is its angular distance from the south point, measured westward on the horizon, to a vertical circle pa.s.sing through the star. The _amplitude_ of a star is its distance from the prime vertical, measured on the horizon, north or south.

For the other measurements used by astronomers in observations of the stars still other circles on the celestial sphere must be imagined. We know that the earth's surface is divided into halves, called the northern and southern hemispheres, by an imaginary circle called the _equator_, whose plane pa.s.ses through the center of the earth and is perpendicular to the earth's axis. If the plane of the earth's equator were infinitely extended it would describe upon the celestial sphere a great circle which would divide that sphere into two hemispheres, just as the plane of the terrestrial equator divides the earth into two hemispheres. This great circle on the celestial sphere is called the _celestial equator_, or, by an older name, the _equatorial_, the significance of which we shall see presently. A star rising due east would traverse this great circle of the celestial sphere and set due west. The path of such a star is represented in Figure 2 by the great circle EMWM', which also represents the celestial equator. All stars rise and set following circles whose planes are parallel to that of the celestial equator and these circles of the celestial sphere are smaller and smaller the nearer they are to the pole, so that stars very near the pole appear to be encircling it in very small concentric circles. Stars in an area around the north celestial pole, whose limits vary with the position of the observer never set for an observer in the northern hemisphere. There is a similar group of stars around the south pole for an observer in the southern hemisphere.

[Ill.u.s.tration: Fig. 2.]

The angle of elevation of the celestial equator to the horizon varies according to the position of the observer. If, for example, the observer were at the north pole of the earth, the north celestial pole would be directly above him and would therefore coincide with the zenith; this would obviously make the celestial equator and the horizon also coincide.

If the observer should pa.s.s slowly from the pole to the terrestrial equator it is clear that the two circles would no longer coincide and that the angle between them would gradually widen until it reached 90. Then the zenith would be on the celestial equator and the north and south poles of the heavens would be on the horizon.

We have still to define a great circle of the celestial sphere that is of equal importance with the celestial equator and the celestial horizon.

This is the sun's apparent yearly path, or the _ecliptic_. We know that the earth revolves about the sun once yearly in an orbit that is not entirely round but somewhat eliptical. Now since the earth, the sun, and the earth's...o...b..t around the sun are always in one plane, it follows that to an observer on the earth the sun would appear to be moving around the earth instead of the earth around the sun. The sun's apparent path, moreover, would be in the plane of the earth's...o...b..t and when projected against the celestial sphere, which is infinite in extent, would appear as a great circle of that sphere. This great circle of the celestial sphere is the ecliptic. The sun must always appear to be on this circle, not only at all times of the year but at all hours of the day; for as the sun rises and sets, the ecliptic rises and sets also, since the earth's rotation causes an apparent daily revolution not only of the sun, moon, and planets but also of the fixed stars and so of the whole celestial sphere and of all the circles whose positions upon it do not vary. The ecliptic is inclined to the celestial equator approximately 23-1/2, an angle which obviously measures the inclination of the plane of the earth's equator to the plane of its...o...b..t, since the celestial equator and the ecliptic are great circles on the celestial sphere formed by extending the planes of the earth's equator and its...o...b..t to an infinite distance. Since both the celestial equator and the ecliptic are great circles of the celestial sphere each dividing it into equal parts, it is evident that these two circles must intersect at points exactly opposite each other on the celestial sphere. These points are called the vernal and the autumnal equinoxes.

We shall next define the astronomical measurements that correspond to terrestrial lat.i.tude and longitude. For some reason astronomers have not, as we might expect, applied to these measurements the terms 'celestial longitude' and 'celestial lat.i.tude.' These two terms are now practically obsolete, having been used formerly to denote angular distance north or south of the ecliptic and angular distance measured east and west along circles parallel to the ecliptic. The measurements that correspond in astronomy to terrestrial lat.i.tude and longitude are called _declination_ and _right ascension_ and are obviously made with reference to the celestial equator, not the ecliptic. For taking these measurements astronomers employ circles on the celestial sphere perpendicular to the plane of the celestial equator and pa.s.sing through the poles of the heavens. These are called _hour circles_. The hour circle of any star is the great circle pa.s.sing through it and perpendicular to the plane of the equator. The angular distance of a star from the equator measured along its hour circle, is called the star's declination and is northern or southern according as the star is in the northern or southern of the two hemispheres into which the plane of the equator divides the celestial sphere. It is evident that declination corresponds exactly to terrestrial lat.i.tude. Right ascension, corresponding to terrestrial longitude, is the angular distance of a heavenly body from the vernal equinox measured on the celestial equator eastward to the hour circle pa.s.sing through the body.

The _hour angle_ of a star is the angular distance measured on the celestial equator from the meridian to the foot of the hour circle pa.s.sing through the star.

[Ill.u.s.tration: Fig. 3.]

It remains to describe in greater detail the apparent movements of the sun and the sun's effect upon the seasons. In Figure 3, the great circle MWM'E represents the equinoctial and XVX'A the ecliptic. The point X represents the farthest point south that the sun reaches in its apparent journey around the earth, and this point is called the _winter solstice_, because, for the northern hemisphere the sun reaches this point in mid-winter. When the sun is south of the celestial equator its apparent daily path is the same as it would be for a star so situated. Thus its daily path at the time of the winter solstice, about December 21, can be represented by the circle Xmn'. The arc gXh represents the part of the sun's path that would be above the horizon, showing that night would last much longer than day and the rays of the sun would strike the northern hemisphere of the earth more indirectly than when the sun is north of the equator. As the sun pa.s.ses along the ecliptic from X toward V, the part of its daily path that is above the horizon gradually increases until at V, the vernal equinox, the sun's path would, roughly speaking, coincide with the celestial equator so that half of it would be above the horizon and half below and day and night would be of equal length. This explains why the celestial equator was formerly called the equinoctial (Chaucer's term for it). As the sun pa.s.ses on toward X' its daily arc continues to increase and the days to grow longer until at X' it reaches its greatest declination north of the equator and we have the longest day, June 21, the summer solstice. When the sun reaches this point, its rays strike the northern hemisphere more directly than at any other time causing the hot or summer season in this hemisphere. Next the sun's daily arc begins to decrease, day and night to become more nearly equal, at A the autumnal equinox[196] is reached and the sun again shapes its course towards the point of maximum declination south of the equator. The two points of maximum declination are called _solstices_.

The two small circles of the celestial sphere, parallel to the equator, which pa.s.s through the two points where the sun's declination is greatest, are called _Tropics_; the one in the northern hemisphere is called the _Tropic of Cancer_, that in the southern hemisphere, the _Tropic of Capricorn_. They correspond to circles on the earth's surface having the same names.

II. By "artificial day" Chaucer means the time during which the sun is above the horizon, the period from sunrise to sunset. The arc of the artificial day may mean the extent or duration of it, as measured on the rim of an astrolabe, or it may mean (as here), the arc extending from the point of sunrise to that of sunset. See _Astrolabe_ ii.7.

There has been some controversy among editors as to the correctness of the date occurring in this pa.s.sage, some giving it as the 28th instead of the 18th. In discussing the accuracy of the reading "eightetethe" Skeat throws light also upon the accuracy of the rest of the pa.s.sage considered from an astronomical point of view. He says (vol. 5, p. 133):

"The key to the whole matter is given by a pa.s.sage in Chaucer's 'Astrolabe,' pt. ii, ch. 29, where it is clear that Chaucer (who, however merely translates from Messahala) actually confuses the hour-angle with the azim.u.t.h.al arc (see Appendix I); that is, he considered it correct to find the hour of the day by noting _the point of the horizon_ over which the sun appears to stand, and supposing this point to advance, with a _uniform_, not a _variable_, motion. The host's method of proceeding was this. Wanting to know the hour, he observed how far the sun had moved southward along the horizon since it rose, and saw that it had gone more than half-way from the point of sunrise to the exact southern point. Now the 18th of April in Chaucer's time answers to the 26th of April at present. On April 26, 1874, the sun rose at 4 hr. 43 m., and set at 7 hr.