« PoprzedniaDalej »
CALOR ET FRIGUS.
The following fragment, which was first printed by Stephens from a MS. in Bacon's own hand, then belonging to the Earl of Oxford, and now in the British Museum (Harl. 6855.), is here reprinted from the original. By the general title Sequela Cartarum, and the heading' Sectio ordinis, &c., it appears to have been designed for the commencement of a methodical enquiry; but it breaks off at so early a stage that no new light can be gathered from it; and the plan upon which Bacon at this time proposed to proceed in these investigations he afterwards materially altered. For the final shape which his speculations concerning Heat and Cold took, see the second book of the Novum Organum.
" This heading is carefully and fairly written out in Bacon's Roman hand at the top of every page ; not in a single line, as it is here printed, but thus :
Calor et Frigus
INQUISITIO LEGITIMA DE CALORE ET FRIGORE.
The sun-beams hot' to sense.
The moon-beams not hot?, but rather conceived to have a quality of cold, for that the greatest colds are noted to be about the full, and the greatest heats about the change. 3 Qu.
The beams of the stars have no sensible heat by themselves; but are conceived to have an augmentative heat of the sunbeams by the instances following.
The same climate arctic and antarctic are observed to differ
in cold, vt. that the antarctic is the more cold, and it is manifest the antarctic hemisphere is thinner planted of
stars. The heats observed to be greater in July than in June; vt. Cor Leonis, Cauda Leonis, Spica Virginis, Sirius,
at which time the sun is nearest the greatest fixed stars,
Spelt whott in MS., and so throughout.
Compare on this point Vol. I. pp. 239. and 624. Since Mr. Ellis's notes on those passages were in type, a more decisive experiment appears to have been made as to the calorific property of the moon's rays. In Mr. C. Piazzi Smyth's “ Notes of Proceedings during the Astronomical Expedition to Teneriffe,” date 14 Oct. 1856, I find the following paragraph : _“Happier was the enquiry into the radiation of the moon, by means of the Admiralty delicate thermomultiplier, lent by Mr. Gassiot. The position of the moon was by no means favourable, being, on the night of the full, 19 deg. south of the equator; but the air was perfectly calm, and the rare atmosphere so favourable to radiation, that a very sensible amount of heat was found, both on this and the following night. The absolute amount was small, being about one-third of that radiated by a candle at a distance of 15 fect; but the perfect capacity of the instrument to measure smaller quantities still, and the confirmatory result of groups of several hundred observations, leave no doubt of the fact of our having been able to measure here a quantity which is so small as to be altogether inappreciable at lower altitudes."
3 The last clause is omitted in the Novum Organum.
noted to cause great heats.
of heat, much more the stars.
The sun-beams have greater heat when they are more perpendicular than when they are more oblique: as appeareth in difference of regions, and the differences of the times of summer and winter in the same region; and chiefly in the difference of the hours of mid-day, morning, evening in the same day.
The heats more extreme in July and August than in May or June ; commonly imputed to the stay and continuance of heat.
The heats more extreme under the tropics than under the line ; commonly imputed to the stay and continuance of heat, because the sun there doth as it were double a cape.
The heats more about three or four of clock than at noon; commonly imputed to the stay and continuance of heat.
The sun noted to be hotter when it shineth forth between clouds, than when the sky is open and serene.
The middle region of the air hath manifest effects of cold, notwithstanding locally it be nearer the sun ; commonly imputed to antiperistasis, assuming that the beams of the sun are hot either by approach or by reflexion, and that falleth in the middle term between both; or if, as some conceive, it be only by reflexion, then the cold of that region resteth chiefly upon distance. The instances shewing the cold of that region are the snows which descend, the hails which descend, and the snows and extreme colds which are upon high mountains. But qu. of such mountains as adjoin to sandy vales, and not
, to fruitful vales, which minister no vapours; or of mountains above the region of vapours, as is reported of Olympus, where any inscription upon the ashes of the altar remained untouched of wind or dew. And note it is also reported that men carried up sponges with vinegar to thicken their breath, the air growing too fine for respiration, which seemeth not to stand with coldness.
The clouds make a mitigation of the heat of the sun. So