# The History of the Royal Society of London/Part 2/Section 40

​In composing Histories after this manner, they resolve to proceed, till they have not only obtain'd an Account of all the great and most substantial Trades, but also of all the less Works, and Private Productions, which are confin'd to some particular Soyls, or Corporations, or Families. As this Stock shall increase, they purpose to make it of General use, either by continuing Printing the most remarkable of them, or by freely exposing them to the view of all, that desire such Informations; provided, that at the same time they receive some, they will also communicate others: And they have allured grounds of confidence, that when this attempt shall be compleated, it will be found to bring innumerable benefits to all practical Arts: When all the secrets of Manufactures shall be discover'd, their Materials describ'd, their Instruments figur'd, their Products represented: It will soon be determin'd, how far they themselves may be promoted, and what new consequences may thence be deduc'd. Hereby we shall see whether all the parts of the most obvious Crafts have been brought to perfection; and whether they may not assist each other, more than has been hitherto endeavour'd: Hereby we shall discern the compass, the power, the changes, the degrees, the ages of them all; and speedily understand, whether their effects have been large enough, and the ways of producing them sufficiently compendious. In short, by this help the worst Artificers will be well instructed, by considering the Methods, and Tools of the best: And the greatest Inventors will be exceedingly inlighten'd; because they will have in their view the labours of many men, many places, and many times, wherewith to compare their own. This is the surest, and ​most effectual means, to inlarge the Inventions: whose Nature is such, that it is apt to increase, not only by mens beholding the Works of greater, but of equal, nay of less Wits than themselves.
Sect. XL. The Conclusion of this Part.In the whole progress of this Narration, I have been cautious to forbear Commending the labours of any Private Fellows of the Society. For this, I need not make any Apology to them; seeing it would have been an inconsiderable Honour, to be prais'd by so mean a Writer: But now I must break this Law, in the particular case of Dr. Christopher Wren: For doing so, I will not alledge the excuse of my Friendship to him; though that perhaps were sufficient; and it might well be allow'd me to take this occasion of Publishing it: But I only do it on the meer consideration of Justice: For in turning over the Registers of the Society, I perceived that many excellent things, whose first Invention ought to be ascrib'd to him, were casually omitted: This moves me to do him right by himself, and to give this separate Account of his indeavours, in promoting the Design of the Royal Society, in the small time wherein he has had the opportunity of attending it.
The first instance I shall mention, to which he may lay peculiar claim, is the Doctrine of Motion, which is the most considerable of all others, for establishing the first Principles of Philosophy, by Geometrical Demonstrations. This Des Cartes had before begun, having taken up some Experiments of this kind, upon Conjecture, and made them the first Foundation of his whole System of Nature: But some of his Conclusions seeming very questionable, because they were only deriv'd from the gross Trials of Balls ​meeting one another at Tennis, and Billiards: Dr. Wren produc'd before the Society, an Instrument to represent the effects of all sorts of Impulses, made between two hard globous Bodies, either of equal, or of different bigness, and swiftness, following or meeting each other, or the one moving, the other at rest. From these varieties arose many unexpected effects; of all which he demonstrated the true Theories, after they had been confirm'd by many hundreds of Experiments in that Instrument. These he propos'd as the Principles of all Demonstrations in Natural Philosophy: Nor can it seem strange, that these Elements should be of such Universal use; if we consider that Generation, Corruption, Alteration, and all the Vicissitudes of Nature, are nothing else but the effects arising from the meeting of little Bodies, of differing Figures, Magnitudes, and Velocities.
The Second Work which he has advanc'd, is the History of Seasons: which will be of admirable benefit to Mankind, if it shall be constantly pursued, and deriv'd down to Posterity. His proposal therefore was, to comprehend a Diary of Wind, Weather, and other conditions of the Air, as to Heat, Cold, and Weight; and also a General Description of the Year, whether contagious or healthful to Men or Beasts; with an Account of Epidemical Diseases, of Blasts, Mill-dews, and other accidents, belonging to Grain, Cattle, Fish, Fowl, and Insects. And because the difficulty of a constant Observation of the Air, by Night and Day, seem'd invincible, he therefore devis'd a Clock to be annex'd to a Weather-Cock, which mov'd a Rundle, cover'd with Paper, upon which the Clock mov'd a black-lead-Pencil; so that the Observer by the Traces of the Pencil on ​the Paper, might certainly conclude, what Winds had blown in his absence, for twelve hours space: After a like manner he contriv'd a Thermometer to be its own Register: And because the usual Thermometers were not found to give a true measure of the extension of the Air, by reason that the accidental gravity of the liquor, as it lay higher or lower in the Glass, weigh unequally on the Air, and gave it a farther contraction or extension, over and above that which was produc'd by heat and cold; therefore he invented a Circular Thermometer, in which the liquor occasions no fallacy, but remains always in one height moving the whole Instrument, like a Wheel on its Axis.
He has contriv'd an Instrument to measure the quantities of Rain that falls: This as soon as it is full, will pour out itself, and at the year's end discover how much Rain has fallen on such a space of Land, or other hard superficies, in order to the Theory of Vapours, Rivers, Seas, &c.
He has devis'd many subtil ways for the easier finding the gravity of the Atmosphere, the degrees of drought and moisture, and many of its other accidents. Amongst these Instruments there are Balances which are useful to other purposes, that shew the weight of the Air by their spontaneous inclination.
Amongst the new Discoveries of the Pendulum, these are to be attributed to him, that the Pendulum in its motion from rest to rest; that is, in one descent and ascent, moves unequally in equal times, according to a line of sines: That it would continue to move either in Circular, or Eliptical Motions; and such Vibrations would have the same Periods with those that are reciprocal; and that by a complication ​of several Pendulums depending one upon another, there might be represented motions like the Planetary Helical Motions, or more intricate: And yet that these Pendulums would discover without confusion (as the Planets do) three or four several Motions, acting upon one Body with differing Periods; and that there may be produc'd a Natural standard for Measure from the Pendulum for vulgar use,
He has invented many ways to make Astronomical Observations more accurate and easy: He has fitted and hung Quadrants, Sextants, and Radii, more commodiously than formerly: He has made two Telescopes, to open with a joynt like a Sector, by which Observers may infallibly take a distance to half minutes, and find no difference in the same Observation reiterated several times; nor can any warping or luxation of the Instrument hinder the truth of it.
He has added many sorts of Retes, Screws, and other devises to Telescopes, for taking small distances and apparent Diameters to Seconds. He has made apertures to take in more or less light, as the Observer pleases, by opening and shutting like the Pupil of the Eye, the better to fit Glasses to Crepusculine Observations: He has added much to the Theory of Dioptrics; much to the Manufacture it self of grinding good Glasses. He has attempted, and not without success, the making of Glasses of other forms than Spherical: He has exactly measured and delineated the Spheres of the Humours in the Eye, whose proportions one to another were only guess'd at before. This accurate discussion produc'd the Reason, why we see things erected, and that Reflection conduces as much to Vision as Refraction.
​He discours'd to them a Natural and easy Theory of Refraction, which exactly answer'd every Experiment. He fully demonstrated all Dioptrics in a few Propositions, shewing not only (as in Keplers Dioptrics) the common properties of Glasses, but the proportions by which the individual Rays cut the Axis, and each other; upon which the Charges (as they are usually called) of Telescopes, or the proportion of the Eye-glasses and Apertures are demonstrably discover'd.
He has made constant Observations on Saturn; and a Theory of that Planet, truly answering all Observations, before the printed Discourse of Hugonius on that Subject appear'd.
He has essay'd to make a true Selenography by measure; the World having nothing yet but Pictures, rather than Surveys and Maps of the Moon. He has stated the Theory of the Moon's Libration, as far as his Observations could carry him. He has compos'd a Lunar Globe, representing not only the Spots, and various degrees of whiteness upon the Surface, but the Hills, Eminencies, and Cavities moulded in solid Work. The Globe thus fashioned into a true Model of the Moon, as you turn it to the Light, represents all the Menstrual phases, with the variety of appearances that happen from the Shadows of the Mountains and Valleys. He has made Maps of the Pleiades, and other Telescopical Stars; and propos'd Methods to determine the great doubt of the Earths motion or rest, by the small Stars about the Pole to be seen in large Telescopes.
In order to Navigation he has carefully pursu'd many Magnetical Experiments; of which this is one of the noblest and most fruitful Speculation. A large Terella is plac'd in the midst of a Plane Board, with a hole ​into which the Terella is half immers'd, till it be like a Globe, with the Poles in the Horizon. Then is the Plane dusted over with steel-filings equally from a Sieve: The Dust by the Magnetical virtue is immediatly figur'd into Furrows, that bend like a sort of Helix, proceeding as it were out of one Pole, and returning into the other: And the whole Plane is thus figur'd like the Circles of a Planisphere.
It being a Question amongst the Problems of Navigation, very well worth resolving, to what Mechanical powrs the Sailing (against the wind especially) was reducible; he shew'd it to be a Wedge: And he demonstrated how a transient Force upon an oblique Plane, would cause the motion of the Plane against the first Mover. And he made an Instrument, that Mechanically produc'd the same effect, and shew'd the reason of Sailing to all Winds.
The Geometrical Mechanics of Rowing, he shew'd to be a Vectis on a moving or cedent Fulcrum. For this end he made Instruments, to find what the expansion of Body was towards the hindrance of Motion in a Liquid Medium; and what degree of impediment was produc'd, by what degree of expansion: with other things that are the necessary Elements for laying down the Geometry of Sailing, Swimming, Rowing, Flying, and the Fabricks of Ships.
He has invented a very curious and exceeding speedy way of Etching. He has started several things towards the emendation of Water works. He has made Instruments of Respiration, and for straining the breath from fuliginous vapours, to try whether the same breath so purify'd will serve again.
He was the first Inventor of drawing Pictures by Microscopical Glasses. He has found out perpetual, at ​least long-liv'd Lamps, and Registers of Furnaces, and the like, for keeping a perpetual Temper, in order to various uses; as hatching of Eggs, Insects, production of Plants, Chymical Preparations, imitating Nature in producing Fossils and Minerals, keeping the Motion of Watches equal, in order to Longitudes and Astronomical uses, and infinite other advantages.
He was the first Author of the Noble Anatomical Experiment of Injecting Liquors into the Veins of Animals: An Experiment now vulgarly known; but long since exhibited to the Meetings at Oxford, and thence carried by some Germans, and publish'd abroad. By this Operation divers Creatures were immediately purg'd, vomited, intoxicated, kill'd, or reviv'd, according to the quality of the Liquor injected. Hence arose many new Experiments, and chiefly that of Transfusing Blood, which the Society has prosecuted in sundry Instances, that will probably end in extraordinary Success.
This is a short account of the Principal Discoveries which Dr. Wren has presented or suggested to this Assembly. I know very well, that some of them he did only start and design; and that they have been since carry'd on to perfection, by the industry of other hands. I purpose not to rob them of their share in the honour: Yet it is but reasonable, that the original Invention should be ascrib'd to the true Author, rather than the Finishers. Nor do I fear that this will be thought too much, which I have said concerning him: For there is a peculiar reverence due to so much excellence, cover'd with so much modesty. And it is not Flattery but Honesty, to give him his just praise; who is so far from usurping the fame of other men, ​that he endeavours with all care to conceal his own.
I have now performed my Promise, and drawn out of the Papers of the Society, an Epitome of the chief Works they have conceiv'd in their Minds, or reduc'd into Practice. If any shall yet think they have not usefully employ'd their time, I shall be apt to suspect, that they understand not what is meant by a diligent and profitable labouring about Nature. There are indeed some men who will still condemn them for being idle; unless they immediately profess to have found out the Squaring of the Circle, or the Philosophers Stone, or some other such mighty Nothings. But if these are not satisfied with what the Society has done, they are only to blame the extravagance of their own Expectations. I confess I cannot boast of such pompous Discoveries: They promise no Wonders, nor endeavour after them: Their Progress has been equal, and firm, by natural degrees, and thorough small things, as well as great: They go leisurably on; but their slowness is not caus'd by their idleness, but care. They have contriv'd in their thoughts, and couragiously begun an Attempt, which all Ages had despair'd of. It is therefore fit that they alone, and not others, who refuse to partake of their burden, should be Judges by what steps, and what pace, they ought to proceed.
Such men are then to be intreated not to interrupt their Labours with impertinent rebukes; they are to remember, that the Subject of their Studies is as large as the Universe: and that in so vast an Enterprise, many intervals and disappointments must be reckon'd upon. Though they do not behold that the Society has already fill'd the world with perfect Sciences; ​yet they are to be inform'd, that the nature of their Work requir'd that they should first begin with immethodical Collections and indigested Experiments, before they go on to finish and compose them into Arts. In which Method they may well be justified, seeing they have the Almighty Creator himself for an Example: For he at first produced a confus'd and scatter'd Light; and reserv'd it to be the Work of another day, to gather and fashion it into beautiful Bodies.
The End of the Second Part.