16. Granting that the clouds may be frozen, it is no wonder if the moon have been seen eclipsed at such time as she hath been almost two degrees above the horizon, the sun at the same time appearing in the horizon; for such an eclipse was observed by Mæstlin, at Tubingen, in the year 1590. For it might happen that a frozen cloud was then interposed between the sun and the eye of the observer. And if it were so, the sun, which was then almost two degrees below the horizon, might appear to be in it, by reason of the passing of his beams through the ice. And it is to be noted that those, that attribute such refractions to the atmosphere, cannot attribute to it so great a refraction as this. Wherefore not the atmosphere, but either water in a continued body, or else ice, must be the cause of that refraction.
By what means many suns may appear at once.
17. Again, granting that there may be ice in the clouds, it will be no longer a wonder that many suns have sometimes appeared at once. For looking-glasses may be so placed, as by reflections to show the same object in many places. And may not so many frozen clouds serve for so many looking-glasses? And may they not be fitly disposed for that purpose? Besides, the number of appearances may be increased by refractions also; and therefore it would be a greater wonder to me, if such phenomena as these should never happen.
And were it not for that one phenomenon of the new star which was seen in Cassiopea, I should think comets were made in the same manner, namely, by vapours drawn not only from the earth but from the rest of the planets also, and congealed into one continued body. For I could very well from hence give a reason both of their hair, and of their motions. But seeing that star remained sixteen whole months in the same place amongst the fixed stars, I cannot believe the matter of it was ice. Wherefore I leave to others the disquisition of the cause of comets; concerning which nothing that hath hitherto been published, besides the bare histories of them, is worth considering.
Of the heads of rivers.
18. The heads of rivers may be deduced from rain-water, or from melted snows, very easily; but from other causes, very hardly, or not at all. For both rain-water and melted snows run down the descents of mountains; and if they descend only by the outward superficies, the showers or snows themselves may be accounted the springs or fountains; but if they enter the earth and descend within it, then, wheresoever they break out, there are their springs. And as these springs make small streams, so, many small streams running together make rivers. Now, there was never any spring found, but where the water which flowed to it, was either further, or at least as far from the centre of the earth, as the spring itself. And whereas it has been objected by a great philosopher, that in the top of Mount Cenis, which parts Savoy from Piedmont, there springs a river which runs down by Susa; it is not true. For there are above that river, for two miles length, very high hills on both sides, which are almost perpetually covered with snow; from which innumerable little streams running down do manifestly supply that river with water sufficient for its magnitude.
CHAP. XXIX.
OF SOUND, ODOUR, SAVOUR, AND TOUCH.
[1.]. The definition of sound, and the distinctions of sounds.—[2.] The cause of the degrees of sounds.—[3.] The difference between sounds acute and grave.—[4.] The difference between clear and hoarse sounds, whence.—[5.] The sound of thunder and of a gun, whence it proceeds.—[6.] Whence it is that pipes, by blowing into them, have a clear sound.—[7.] Of reflected sound.—[8.] From whence it is that sound is uniform and lasting.—[9.] How sound may be helped and hindered by the wind.—[10.] Not only air, but other bodies how hard soever they be, convey sound.—[11.] The causes of grave and acute sounds, and of concent.—[12.] Phenomena for smelling.—[13.] The first organ and the generation of smelling.—[14.] How it is helped by heat and by wind.—[15.] Why such bodies are least smelt, which have least intermixture of air in them.—[16.] Why odorous things become more odorous by being bruised.—[17.] The first organ of tasting; and why some savours cause nauseousness.—[18.] The first organ of feeling; and how we come to the knowledge of such objects as are common to the touch and other senses.
The definition of sound, and the distinction of sounds.