Note Book 4. Chap. 3. Note 28 — BOOK IV.

[bb] That the Air is the Subject, or Medium of Sound, is manifest from the Experiments in rarefied and condensed Air. In an unexhausted Receiver, a small Bell may be heard at the Distance of some Paces; but when exhausted, it can scarce be heard at the nearest Distance: And if the Air be compressed, the Sound will be louder, proportionably to the Compression or Quantity of Air crouded in, as I have often tried my self, and may be seen in Mr. Hawksbee’s curious Experiments, p. 97. Also his Experiments in Phil. Trans. Nᵒ. 321.

Kircher saith, he took one of these Trumpets of fifteen Palms length, along with him to the Mons Eustachianus, where he convocated 2200 Persons to Prayers, by means of the unusual Sound, at two, three, four, and five Italian Miles Distance.

With these Bellowing Trumpets, I shall join some Bellowing-Caves for the Reader’s Diversion. Ol. Magnus describes a Cave in Finland, near Viburg, called Smellen, into which, if a Dog, or other Living Creature be cast, it sends forth so dreadful a Sound, that knocks down every one near it. For which Reason they have guarded the Cave with high Walls, to prevent the Mischiefs of its Noise. Vid. Ol. Magn. Histor. l. 11. c. 4. Such another Peter Martyr saith is in Hispaniola, which, with a small Weight cast into it, endangers Deafness at five Miles Distance. And in Switzerland, Kircher saith, in the Cucumer-Mountain is a Pit that sends out both a dreadful Noise and a great Wind therewith; and that there is a Well in his Country 3000 Palms deep, whose Sound is equal to that of a great Gun. Vid. Kirch. Phonurg.

Ol. Magnus speaking of the vast high Mountains of a Northern Province, call’d Angermannia saith, Ubi bases eorum in profundissimo gurgite stantes, casu aliquo, vel proposito Nautæ accesserint, tantum horrorem ex altâ fluctuum collisione percipiunt, ut nisi præcipiti remigio, aut valido vento evaserint, solo pavore ferè exanimes fiant, multoque dierum curriculo, ob capitis turbationem, pristinæ mentis, & sanitatis compotes vix evadant. Habent bases illorum montium in fluctuum ingressu & regressu tortuosas rimas, sive scissuras, satis stupendo naturæ opificio fabricatas, in quibus longâ varagine formidabilis ille Sonitus quasi subterraneum tonitru generatur. Ol. Magn. l. 2. c. 4. See also Chap. 12.

Neither doth this succeed only in forced Rarefactions and Condensations of the Air, but in such also as are natural; as is evident from David Frœdlichius in Varenius, upon the highest Eminencies of Carpathus, near Kesmarckt in Hungary. The Story of Frœdlichius is this, Ego Mense Junii 1615. tum adolescens, sublimitatem horum montium, cum duobus comitibus Scholaribus, experiri volens, ubi, cùm in primæ rupis vertice, magno labore, me summum terminum assecutum esse putarem, demum sese obtulit alia multo altior cautes, ubi pervasta eaque vacillantia saxa (quorum unum, si loco à viatore dimovetur——aliquot centena——rapit, & quidem tanto cum fragore, ut illi metuendum sit nè totus Mons corruat, eumque obruat) enixus essem, iterum alia sublimior prodiit, &c. donec summo vitæ periculo ad supremum cacumen penetraverim. Ex declivioribus montibus cùm in subjectas valles,——nil nisi obscuram noctem, aut cœruleum quid, instar profundi aeris, quod vulgò sudum cœlum appellatur, observare potui, mihique videbar, si de monte caderem, non in terram, sed recte in solum me prolapsurum. Nimiá enim declivitate, species visibiles extenuatæ & hebetatæ fuerunt. Cum verò altiorem montem peterem, quasi intra nebulas densissimas hærebam——Et cùm non procul à summo vertice essem de sublimi quiescens prospexi & animadverti iis in locis, ubi mihi antea videbar intra nebulas hæsisse, compactas atque albas sese movere nubes, supra quas, per aliquot milliaria, & ultra terminos Sepusi commodus mihi prospectus patuit. Alias tamen etiam nubes altiores, alias item humiliores, necnon quasdam æqualiter à terrâ distantes vidi. Atque hinc tria intellexi, 1. Me tum transivisse principium media Aeris regionis. 2. Distantiam nubium à terrâ, non esse æqualem.——3. Distantiam nubium——non 72 Mill. Ger. ut quidam——sed tantum dimidiatum Mill. Ger. In summum montis verticem cùm pervenissem, adeò tranquillum & subtilem aërem ibi offendi, ut nè pili quidem motum sentirem, cùm tamen in depressioribus ventum vehementem expertus sim: unde collegi summum cacumen istius montis Carpathici ad Mill. Germ. à radicibus suis imis exsurgere, & ad supremam usque aëris regionem, ad quam Venti non ascendunt, pertingere. Explosi in eâ summitate Sclopetum: quod non majorem sonitum primò præ se tulit, quàm si ligillum vel bacillum confregissem; post intervallum autem temporis murmur prolixum invaluit, inferioresque montis partes, convalles & sylvas opplevit. Descendendo per nives annosas intra convalles, cùm iterum Sclopetum exonerarem, major & horribilior fragor, quàm ex tormento capacissimo inde exoriebatur: hinc verebar nè totus mons concussus mecum corrueret: duravitque hic sonus per semiquadrantem horæ usque dum abstrusissmas cavernas penetrâsset, ad quas aër undiq; multiplicatus resiliit.——In his celsis montibus, plerumq; ningit grandinatve mediâ astate, quoties nempe in subjectâ & vicinâ planitie pluit, utì hoc ipsum expertus sum. Nives diversorum annorum ex colore & cortice duriore dignosci possunt. Varen. Georg. Gen. l. 1. c. 19. Prop. ult.

The Story being diverting, and containing divers Things remarkable, I have chosen to note the whole of it (altho’ somewhat long) rather than single out the Passages only which relate to the diminishing the Sound of his Pistol, by the Rarity of the Air at that great Ascent into the Atmosphere; and the magnifying the Sound by the Polyphonisms or Repercussions of the Rocks, Caverns, and other Phonocamptick Objects below in the Mount.

But ’tis not the Air alone that is capable of the Impressions of Sound, but the Water also, as is manifest by striking a Bell under Water, the Sound of which may plainly enough be heard, but it is much duller, and not so loud; and it is also a fourth deeper, by the Ear of some great Judges in Musical Notes, who gave me their Judgments in the matter. But Mersenne saith, a Sound made under Water, is of the same Tone or Note, if heard under Water; as are also Sounds made in the Air, when heard under Water. Vid. Mersen. Hydraul.

Having mentioned the hearing of Sounds under Water, there is another Curiosity worth mentioning, that also farther proves Water to be susceptible of the Impressions of Sound, viz. Divers at the bottom of the Sea, can hear the Noises made above, only confusedly. But, on the contrary, those above cannot hear the Divers below. Of which an Experiment was made, that had like to have been fatal: One of the Divers blew an Horn in his Diving-Bell, at the bottom of the Sea; the Sound whereof (in that compressed Air) was so very loud and irksome, that stunned the Diver, and made him so giddy, that he had like to have dropt out of his Bell, and to have been drowned. Vid. Sturmii Colleg. Cur. Vol. 2. Tentam. 1.