An astrological discourse with mathematical demonstrations proving the powerful and harmonical influence of the planets and fixed stars upon elementary bodies in justification of the validity of astrology : together with an astrological judgment upon the great conjunction of Saturn & Jupiter, 1603 / written by that worthy, learned gentleman, Sir Christopher Heydon, Knight ; and now published by Nicholas Fiske ...

CHAP. VIII.

Other qualities concomitate Light, as well as Heat.

ANd now to prosecute these things in order: First, I affirm, That al∣though we see Heat and Light to descend joyntly with the Beams of the Sun, yet

it doth not concomitate the light of all the Stars; for that heat is nei∣ther the substance of the light, (for assertion whereof Scaliger justly repre∣hendeth Cardane,) nor more to be con∣founded with light then sight, then sight is to be confounded with touch, where∣of Light and Heat are proper Objects. For as we cannot feel the Light, nor see the Heat; so those Senses which are not always joyntly exercised together (as we see, and not feel, and feel, and not see) do teach us, that Light and Heat are di∣vers qualities, and both in reason and na∣ture may be conceived to subsist the one without the other. This will best ap∣pear by the diffinition of both, which evermore expresseth the nature of the thing in question. Forasmuch therefore as Heat is that quality which doth con∣gregate homogeneal things, and separate those that are heterogeneal, which agree∣eth not to the property of the Light, which is brought unto us by the Beams of the Stars, the same being defined (ac∣cording to Alhazen and Vitellio) to be only The Species or Image of the inhe∣rent Light of the Sun or Star from

whence it is sent: There is nothing more evident then that that Heat which is con∣veyed unto us with the beams of the Sun, is of a divers nature from the light thereof. For both Sence and Experience do prove, That Heat is no Image or simi∣litude, but a real and active quality, which how it should subsist in an Image as in the subject, or how Light should subsist in Heat, being likewise an accidental quality, are difficulties which in my judg∣ment will not easily be answered, except we can prove, that one accident may be the subject of another, which is against all Philosophy. This then alone, although it doth sufficiently prove, that Light and Heat are two divers qualities; yet to make it more apparent, dayly observation doth shew, That one may be and remain in the absence of the other, as we see in Attrition, where Heat is excited without Light, and so we may exclude the Light, when nevertheless the heat of the Sun shall remain. And though the Earth, and the rest of the Elements, retein the im∣pression of the former day, yet doth nei∣ther the Earth, Air, or Water, shine after the Sun is set: Wherefore if Heat may

thus exist, and be separated from the light; and it be also true (as before hath been shewed) that the one cannot sub∣sist in the other, what may be more clear then that for these Reasons Light and Heat are two diverse qualities, and that Light can neither be the essence of Heat, nor Heat of Light? Truly therefore doth Durandus distinguish of their properties, teaching us, that the property of Light is only to illuminate, and that it is not of the essence thereof either to heat or in∣frigidate; Sed (saith he) duntaxat me∣rito corporis in quo inest, ut si virtute calidum sit, &c. So then the heat, which accompanieth the light of the Sun, is not to be said any property of light, but in truth to be referred to the Suns occult and specifick Virtue: as with like rea∣son I do affirm, and hereafter will prove, That the rest of the first qualities, toge∣ther with the special properties of every Star, doth accompany Light as well as Heat. For it is clear, that there be many lightsom bodies which do not heat, but are rather actually cold, as for example, the Diamond, Carbuncle, and other pre∣cious Stones, besides the Eyes, Heads,

and Scales of Fishes, and the Sea it self, which in tempestuous weather doth re∣present huge mountains of light. Yet to affirm that the Sea burns, would be re∣puted by the common Proverb, no better then a plain lye. So false is it, that light is always the cause of heat, and proceed∣eth only from such bodies as are of a hot nature; which I could yet further am∣plifie by experience that I have made in Reflections, it being certain that Spheri∣cal Concaves, or Parabolical Sections, will as sensibly reflect the actual cold of Snow or Ice, as it will the heat of the Sun. Wherefore if Cold may accompa∣ny the reflected Light, why not the origi∣nal Light it self? Neither do I desire herein my bare word to go for payment, but do further remit him that shall call this in doubt unto his own practise, and the Testimonies of Maginus, who, in the Representations of his Glass sent to the Emperor, doth confirm the same in these words: Species esse sensu tactus perceptibilis, ut apparet ex lumine can∣delae, item ex nive & glacie infrigidante per suam imaginem remotè admodum. And my self have often made the like

tryal of the full Moon, which neverthe∣less is reflected without any heat at all that sense can perceive, notwithstanding that the same Glass doth sensibly rever∣berate heat with the light of a small can∣dle, and reflecteth the beams of the Sun with that force, that it inflameth all com∣bustible matter in an instant, and causeth Lead to run. Whereunto then may it be imputed, that the Moon shining with her borrowed light, doth not sensibly warm, as well when it is projected from the Sun? Will they answer that the Suns light is debilited by reflection from the Moon? But if they maintain heat always to accompany light, then this is no an∣swer. And though I should yield that it may weaken the heat also, and cause calefaction in a lesser degree, yet this doth not satisfie how so glorious a Light as the full Moon doth yield, especially in Winter, should be deprived of all heat, when the same is collected, re-united, and multiplied again, in which case as well all Beams are as well strengthened by reflection, as weakened without his help. Add hereunto, that the greatest Frosts happen in the fairest Moon-shine

nights, which proveth Cold to accom∣pany her light. VVherefore I rather af∣firm this to be another notable Argu∣ment, proving Light of an indifferent na∣ture, neither hot nor cold of it self, but to participate of the quality of the star, or other body from whence it is reflect∣ed, seeing the same light which from the Sun causeth heat, hath no such qua∣lity reflected from the Moon, but rather the contrary, and divers from it, the force thereof chiefly shewing it self in cold and moisture. But if Keplers opinion were true, that Cold were nothing but a meer Privation, this could not be: and there∣fore leaving that which hath been al∣ready alledged to the Judgment of the learned, I hold it very material, accord∣ing to the order formerly propounded, to prove next, That Cold is a positive quality.

Notes

• Exercitat. 75.
• Heat or Hotness defined.
• Light defi∣ned, or ra∣ther light∣somness.
• Light in many na∣tural Bo∣dies, which yet be actu∣ally cold.
• Cold ac∣companieth reflected Light.
• The light of the Moon not to be hot, found by reflexi∣on.