Plus ultra, or, The progress and advancement of knowledge since the days of Aristotle in an account of some of the most remarkable late improvements of practical, useful learning, to encourage philosophical endeavours : occasioned by a conference with one of the notional way / by Jos. Glanvill.

CHAP. VII. That Useful Knowledge is to be aided by Instruments. Modern Instances of such. Of the Telescope, Mi∣croscope, and Thermometer. (Book 7)

THus, Sir, I have touched upon some of the Improvements of the ARTS that search into the recesses and intrigues of Nature, with which latter Ages have assist∣ed Philosophical Inquiries. And in these I see I have struck farther than I was aware, in∣to the account of those things also which lead us to the grosser Phaenomena; and my Remarques about Geography are all of that nature. However I shall not alter my Me∣thod; but after I have discours'd the IN∣STRVMENTS I mentioned for Use∣ful Knowledge, I shall consider somewhat of NATVRAL HISTORY, which reports the Appearances, and is fundamen∣tally necessary to all the Designs of Science. As for the INSTRVMENTS then, that are next, before I come to give you

the Notes I intend concerning them, I ob∣serve, That

The Philosophy that must signifie either for Light or Vse, must not be the work of the Mind turned in upon it self, and on∣ly conversing with its own Idaeas; but It must be raised from the Observations and Applications of Sense, and take its Accounts from Things as they are in the sensible World. The Illustrious Lord Bacon hath noted this as the chief cause of the unpro∣fitableness of the former Methods of know∣ledge, viz. That they were but the Exer∣cises of the Mind, making Conclusions, and spinning out Notions from its own native store; from which way of proceeding, no∣thing but Dispute and Air could be expect∣ed. 'Twas the fault that Great Man found in the Ancients, That they flew presently to general Propositions, without staying for a due information from Particulars, and so gradually advancing to Axioms: Whereas the Knowledge from which any thing is to be hoped, must be laid in Sense, and rai∣sed not only from some few of its ordinary Informations; but Instances must be ag∣gregated, compared, and critically inspected, and examined singly and in consort. In or∣der to which Performances, our Senses

must be aided; for of themselves they are too narrow for the vastness of things, and too short for deep Researches: They make us very defective and unaccurate Reports, and many times very deceitful and fallacious ones. I say therefore, they must be assisted with Instruments that may strengthen and rectisie their Operations. And in these we have mighty advantages over Aristotle and the Ancients; so that much greater things may well be expected from our Philosophy, than could ever have been performed by theirs, though we should grant them all the superiority of Wit and Vnderstanding their fondest Admirers would ascribe to those Sages. For a weak hand can move more weight by the help of Springs, Wheels, Leavers, and other Mechanick Powers, than the strongest could do without them. And that we really have these Advantages, must be shewn by Instance: I mentioned Five that are considerable to that purpose, which I took notice of among many others; and they were the TELESCOPE, MI∣CROSCOPE, THERMOMETER, BAROMETER, and AIR-PVMP.

(I.) The TELESCOPE is the most excellent Invention that ever was, for assist∣ing the Eye in remote Discoveries. The di∣stance

of the Heavens is so vast, that our unaided Senses can give us but extreamly imperfect Informations of that Upper World; And the Speculations that Anti∣quity hath raised upon them, have for the most part been very mean, and very false: But these excellent Glasses bring the Stars nearer to us, and acquaint us better with the immense Territories of Light: They give us more Phaenomena, and truer Ac∣counts; disperse the shadows and vain Ima∣ges of the twilight of naked sense, and make us a clearer and larger prospect. By these Advantages they inlarge our Thoughts, and shew us a more magnificent Representa∣tion of the Vniverse: So that by them the Heavens are made more amply to declare the Glory of God, and we are help'd to nobler and better-grounded Theories. I have mentioned in my Account of the Advance of Astronomy, some of the most remarka∣ble Discoveries that have been made by these Tubes, which exceedingly transcend all the Imaginations of Elder Times; and by the further improvement of them, other things may be disclosed as much beyond all ours. And the present Philosophers are so far from desiring that Posterity should sit down con∣tented with their Discoveries and Hypothe∣ses,

that they are continually sollicitous for the gaining more helps to themselves, and those that shall follow, for a further pro∣gress into the knowledge of the Phaenome∣na, and more certain judgments upon them. So that these Glasses are exceedingly better∣ed since their Invention by Metius, and ap∣plication to the Heavens by Galilaeo; and several ingenious Members of the ROY∣AL SOCIETY are now busie about improving them to a greater height. What success and informations we may expect from the Advancements of this Instrument, it would perhaps appear Romantick and ri∣diculous to say; As, no doubt, to have talk'd of the spots in the Sun, and vast in∣equalities in the surface of the Moon, and those other Telescopical certainties, before the Invention of that Glass, would have been thought phantastick and absurd. I dare not therefore mention our greatest hopes: but this I adventure, That 'tis not unlikely but Posterity may by those Tubes, when they are brought to higher degrees of perfection, find a sure way to determine those mighty Questions, Whether the Earth move? or, the Planets are inhabited? And who knoweth which way the Conclusi∣ons may fall? And 'tis probable enough,

that another thing will at last be found out, in which this lower World is more immediately concerned, by Telescopical Observations, which is, the most desired Invention of Longitudes; upon which must needs ensue yet greater Improvements of Navigation, and perhaps the Discovery of the North-west Passage, and the yet unknown South. Whatever may be thought of these Expectations by Vulgar and narrow Minds, whose Theories and Hopes are confin'd by their Senses, those that consider, that one Experiment discovered to us the vast Ame∣rica, will not despair. But 'tis time to pass from this, to a second Modern Aid, where∣by our Sight is assisted, which is,

(II.) The MICROSCOPE. The Secrets of Nature are not in the greater Masses, but in those little Threds and Springs which are too subtile for the gros∣ness of our unhelp'd Senses; and by this In∣strument our eyes are assisted to look into the minutes and subtilties of things, to discern the otherwise invisible Schematisms and Structures of Bodies, and have an ad∣vantage for the finding out of Original Mo∣tions; To perceive the exactness and curi∣osity of Nature in all its Composures; And from thence take sensible Evidence of the

Art and Wisdom that is in its Contrivance; To disclose the variety of living Creatures that are shut up from our bare Senses, and open a kind of other World unto us, which its littleness kept unknown. This Instru∣ment hath been exceedingly improved of late, even to the magnifying of Objects a thousand times, and many useful Theories have been found and explicated by the no∣tices it hath afforded; as appears by the Microscopical Writings of those ingenious Mechanicks, Members of the ROYAL SOCIETY, Dr. Power and Mr. Hooke.

But (III.) The THERMOMETER was another Instrument I mentioned, which discovers all the small unperceivable varia∣tions in the heat or coldness of the Air, and exhibits many rare and luciferous Phaenome∣na, which may help to better Informations about those Qualities, than yet we have any. And as to this, I observe with the great Verulam, and the other Bacon the Il∣lustrious Mr. Boyle, That Heat and Cold are the right and left hand of Nature. The for∣mer is the great Instrument of most of her Operations; and the other hath its Interest. And yet the Philosophy of Aristotle hath nei∣ther done nor as much as attempted anything toward the Discovery of their

Natures; but contented it self with the jejune, vulgar, and general description, That Heat is a Quality that gathereth together things of a like nature, and severs those that are unlike; and Cold congregates both. But now if we will know any thing deeply in the business of Rarefaction and Condensation, the Doctrine of Meteors, and other mate∣rial Affairs of Nature, other Accounts about these things must be endeavoured; and the bare informations of our Senses, are not exact enough for this purpose; for their Reports in this kind are various and uncer∣tain, according to the temper and disposition of our Bodies, and several unobserved acci∣dental mutations that happen in them. This Instrument therefore hath been invented to supply their defects; and it gives far more constant and accurate, though perhaps not always infallible Relations: but the justest are afforded by the Sealed Thermometer. And besides the Vses of this Instrument I suggested, it will help very much in fra∣ming the History of Weather, which may be applied to many excellent purposes of phi∣losophy, and services of Life.