New experiments physico-mechanicall, touching the spring of the air, and its effects (made, for the most part, in a new pneumatical engine) : written by way of letter to the Right Honorable Charles, Lord Vicount of Dungarvan, eldest son to the Earl of Corke / by the Honorable Robert Boyle, Esq.

A Summary of the chief Matters treated of in this Epistolical Discourse.

THe Proaemium, wherein is set down the oc••asion of this Discourse, 1. The mo∣tives that induc'd the Author thereunto, 2 &c. The hints he received, 5. The things where∣in this Engine excels any that have yet been made use of, 6 &c. The description of the Engine and its parts, 8 &c. The way of pre∣paring and using it, 15 &c. The division of the Experiments tryable thereby into two sorts, and the difficulty of excluding the Air.

18 &c.

The first Experiment, touching the man∣ner of pumping out the Air, and by what de∣grees the Receiver is emptyed, ••0, &c. A di∣gression touching the Spring or Elastical power of the Air, with an attempt for a Me∣chanical Explication thereof, necessary to be premis'd for the explanation of the Phaeno∣mena, exhibited in this and the subsequent Experiments.

22 &c.

The second Experiment, touching the pres∣sure of the Air against the sides of the Bodies it invirons, 37 &c. with a digressive Ex∣plication of the pressure of the Air included within an ambient Body.

39 &c.

The third Experiment, touching the force requisite to draw down the Sucker, 42 &c. The Opinion of an eminent Modern Naturalist examin'd.

44 &c.

The fourth Experiment, touching the swelling of a Bladder; with the degrees by which it increases, 45 &c. Another Opini∣on of a Learned Author examin'd.

48 &c.

The fifth Experiment, touching the break∣ing of a Bladder in the Receiver, 49 &c. And of another by heat.

52

The sixth Experiment, of divers ways by which the elastical expansion of the Air was measur'd.

52 &c

The seventh Experiment, touching what Figure does best resist the pressure of the Air.

62 &c.

The eighth Experiment, tending to a fur∣ther Demonstration of the former, from the breaking of glass a Helmet inward.

64 &c.

The ninth Experiment, contains a fur∣ther confirmation from the breaking of a Glass outward, 66 &c. with an Experiment to prove, that these Phaenomena proceed not from an invincible Fuga vacui 69. A de∣scription of other small Receivers, and their Conveniencies, 70 &c. A Receipt for the making of a Composition to Cement crackt Glasses.

73

The tenth Experiment, touching the fla∣ming of Candles inclosed in the Receiver.

74 &c.

The eleventh Experiment, touching the burning of Coals, 78. And the lasting of the excandescence of an included piece of I∣ron.

80.

The twelfth Experiment concerning the burning of Match.

82

The thirteenth Experiment, concerning the further prosecution of the preceding, tending to prove the extinction of the Fire in the former Experiments, not to have proceeded from the pressure of the Fire by the Fumes, 84. Some remarkable Circumstan∣ces of it, 86. The Experiment of Match try'd in a small Receiver.

87

The fourteenth Experiment, touching the striking Fire, and kindling of Powder with the Lock of a Pistol in the evacuated Recei∣ver.

88 &c.

The fifteenth Experiment, touching the unsuccessfulness of kindling included Bo∣dies with a burning Glass, and the Au∣thors intention to prosecute it further.

102

The sixteenth Experiment, concerning the operation of the Loadstone.

105, &c.

The seventeenth Experiment, touching the gradual descent of the Quick-silver in the Torricellian Experiment, 106 &c. Some observable Circumstances concerning it, 112 &c. The same Experiment try'd in one of the small Receivers, 115. How this Experiment may be made use of to know the strength of the pressure of the Air for every degree of Rarefaction, 1••6 &c. The tryal of the same Experiment in a Tube not two foot long, 118. The raising of the Mer∣curial Cylinder, by the forcing of more Air into the Receiver, 119. Some Allegations for and against a Vacuum consider'd, 1••0 &c. Some Advertisements concerning the inconveniencies that may arise from the di∣versity of measures made use of for the defi∣ning the Altitute of the Mercurial Cylinder; and from the neglect of little parcels of Air apt to remain between the Mercury and the concave surface of the Tube, 123 &c. Some Expedients for the more exact filling the Tube, 127. The height the Author once found of the Mercurial Cylinder, according to En∣glish measure.

128.

The eighteenth Experiment, containing a new Observation touching the variation of the height of the Mercurial Cylinder in the same Tube, with an offer at the reason

thereof.

129 &c.

The 19^th Experiment, touching the sub∣siding of a Cylinder of Water, 140 &c. The same try'd in a small Receiver.

143

The 20^th Experiment, touching the Ela∣ter of Water, with a digressive Experiment to the same purpose

144 &c.

The 21 Experiment, being a prosecution of the former Enquiry, by Experimenting the Generation of Bubbles under Water, a recital of some notable Circumstances, with some observable Corollary's deduc'd there∣from.

147 &c.

The 22^d Experiment, tending to a deter∣mination of the Enquiry propos••d in the for∣mer Experiment, by proving the matter of these Bubbles from their permanency to be Air: The Experiments try'd in the great and small Receivers, evincing the same thing, 155 &c. An Experiment wherein there appear'd Bubbles in Quick-silver, 160. The Authors Inference, 162. A di∣gressive Enquiry, whether or no Air may be generated anew; with several Histories and Experiments, tending to the resolving and clearing thereof, 162 &c. The Authors ex∣cuse for so long a Digression.

181

The 23^d Experiment, containing a fur∣ther Enquiry touching Bubbles made with

common and distill'd Water.

182

The 24^th Experiment, wherein the inqui∣ry is prosecuted with other Liquors, as with Sallet Oyl, Oyl of Turpentine, a Solution of Tartar, Spirit of Vinegar, Red-wine, Milk, Hen's Eggs, Spirit of Urine, Spirit of Wine and Water, Spirit of Wine. 187 &c. The wonderful expansion of the Spirit of Wine.

194

The 25^th Experiment, touching the ex∣pansion and gravity of the Air under wa∣ter.

195 &c.

The 26^th Experiment, touching the Vi∣brations of a Pendulum.

202 &c.

The 27^th Experiment, touching the pro∣pagation of sound: And the Authors inten∣tion of trying some other Experiments, for the further elucidation thereof.

210 &c.

The 28 Experiment, touching the sudden ••ruption of Bubbles from the water, when the airs pressure was speedily remov'd.

214

The 29 Experiment, touching the cause of the ascent of Fumes and Vapors, wherein 'tis prov'd (from the several motions, which the Fumes of a strange smoaking Liquor, of the Authors, were observ'd to have in the Re∣ceiver, upon the exsuction of the Air) that the reason of their ascent proceeds from the gravity of the ambient air, and not from any positive levity of their own.

217 &c.

The 30 Experiment, concerning the na∣ture of a fluid Body, illustrated by the exam∣ple of smoak which in several circumstances seems very much to resemble the property of a fluid Body, 224 &c. A conjecture of the cause of the Suns undulation.

228

The 31 Experiment, concerning the Phae∣nomena of two flat Marbles exactly plain'd and wrought together, and the true reason thereof, 229. The Authors intention for the further prosecution thereof, & what hindred him; the reason why the under Marble did not fal from the upper (being onely conjoynd with Spirit of Wine) when the Receiver was evacuated. And a notable relation concern∣ing the cohesion of flat Bodies.

231 &c.

The 32 Experiment, touching the forcible pressure of the Air against the outward su∣perficies of a Valve, fasten'd upon the stop∣cock of the Receiver. The Diameter of it, and the weight it sustain'd.

233 &c.

The 33 experiment, touching the great pres∣sure of the Air against the under superficies of the Sucker, 236 &c. what weight was re∣quisite to depress it, & what weight it would lift and carry up with it, 239 &c. what im∣provement & use there may be made of this experiment, 242. A Discourse touching the nature of Suction, proving that fuga vacui is not the adequate cause thereof.

243 &c.

The 34^th Experiment, containing several attempts for the weighing of light Bodies in the exhausted Receiver.

258 &c.

The 35^th Experiment, touching the cause of ••iltration, and the rising of Water in Siphons, 262 &c. A relation of a new kinde of Siphon, of the Authors, upon the occasion of trying the Experiment lately observ'd by some French-men, and fur∣ther improv'd by himself; and some conje∣ctures touching the cause of the exhibited Phaenomena.

267 &c.

The 36^th Experiment, touching the weigh∣ing of a parcel of Air in the exhausted Ves∣sel; and some other Observations for the ex∣plication thereof, 272 &c. An accidental Experiment, tending to the further confir∣mation of the Authors Reflections upon the first Experiment; with a digressive Obser∣vation, noting the subtil penetrancy of some Spirits, to exceed by far that of the Air, 275 &c. And some other Experiments to shew the difficulty of the ingress of the Air into the pores or holes of some bodies into which Wa∣ter will readily insinuate it self, 279 &c. with a conjecture at the cause thereof, 282. The Author returns to the prosecution of the in∣quiry after the gravity of the Air: But first, (upon the occasion of the tenacity of a thin

Bubble of Glass) sets down his thoughts con∣cerning the strange exuperancy of strength in Air, agitated by heat, above what the same has unagitated, 283 &c. And then pro∣ceeds to the examination of the weight of the Air by an Aeolipile, and compares the result thereof, with that of Mersennus, 286. The Opinions and Experiments of divers Au∣thors, and some of his own, touching the proportion of weight betwixt Water and Air, are compar'd and examin'd by the Author, 288. The result thereof, 290. Mersennus his observation reconcil'd, with that of the Author; and the proportion between the gra∣vity of Water and Air about London, 291 &c. After the recital of the Opinions of se∣veral Writers, touching the proportion of gravity between Water and Quick silver, the Author sets down his own tryals, made several ways, together with his conclusion therefrom, 293 &c. The use he makes of this inquiry for the ghessing at the height of the Atmosphere, 297. What other Experiments are requisite to the determination thereof.

299 &c.

The 37^th Experiment, touching the strange and odde Phaenomenon, of the sudden flash∣es of light in the cavity of the Receiver; the several circumstances and difficulties of it,

with some attempts towards the rendering at reason thereof, 301, &c. The Difficulty of so doing fur∣ther shewn from the consideration of the various changes of Air which doe not immediatly fall un∣der our senses, 315. this last proposition prou'd by severall observations.

316.

The 38. Experiment, touching the freezing of water, 319. &c. A problem, (concerning the great force wherewith a freezing Liquor extends its selfe,) propos'd upon the Consideration of divers admirable effects wrought th••reby.

320 &c.

The 39. Experiment, containing an inquisition after the temperature of the substance that remain'd in the cavity of the Receiver, after the Air was well exhausted. The relation of a Phaenomenon, seeming to proceed from the sw••lling of the Glass. With an advertisement concerning the pliableness of Glass in small prices.

322. &c.

The 40. Experiment, touching the difficulty that occur'd in making tryall whether rarified Air were able to sustaine flying insects.

326. &c

The 41. Experiment, Exhibiting severall try∣alls touching the respiration of divers sorts of ani∣malls included in the Receiver, 328, &c. With a digression conteining some doubts touching respira∣tion wherein are delivere•• severall Experiments re∣lating thereunto.

335 &c.

The 42. Experiment, touching the differing o∣peration▪ of corrosive Liquors in the emptied Receiver and in the open Air.

384

The 43. Experiment, touching the spontaneous E∣bullition of warm Liquors in the exhausted Receiver.

388

The Conclusion.

394