Munday, Decemb. 7. 1665.
Of Monsieur de Sons Progress in working Parabolar Glasses.
SInce what was mentioned in the immediately precedent Tract, touching Monsieur de Son's noble attempt of grinding Glasses of a Parabolical Fgure, the Publisher of these Papers hath himself seen two Eye-glasses of that shape, about one inch & a half deep and one inch and a quarter broad, wrought by this Eminent Artist with a rare Steel-instrument of his own contrivance and workmanship, and by himself also polished to admiration. And certainly it will be wondred at by those, who shall see these Glasses, how they could be truly wrought to such a Figure, with such a Cavity; & yet more, when they shall hear the Author undertake to excavate other such Eye-Glasses to above two inches, and Object-glasses of five inches Diameter. He hath likewise already begun his Object-glasses for the mentioned two Ocular ones, of the same Figure of about two inches Diameter, which are to be left all open, yet without causing any colours. Of all which 'tis hoped, that shortly a fuller and more particular accompt will be given.
This Inquisitive Philosopher in a letter of his, lately written to his correspondent in London, takes occasion to discourse of his considerations concerning those Changes, mentioned in the Title, as followes;
I have (saith he) sometimes thought upon the Changes, which 'tis likely, the supposed Inhabitants of the Moon might discover in our Earth, to see, whither reciprocally I could observe any such in the Moon. For example, methinks, that the Earth would to the people of the Moon appear to have a different face in the several seasons of the year; and to have another appearance in Winter, when there is almost nothing green in a very great part of the Earth; when there are Countries all covered with snow, others, all covered with water, others, all obscured with Clouds, and that for many weeks together: Another in Spring, when the Forrests and Fields are green. Another in Summer, when whole Fields are yellow &c. Me thinks, I say, that these changes are considerable enough in the force of the reflexions of Light to be observed, since we see so many differences of Lights in the Moon. We have Rivers considerable enough to be seen, and they enter far enough into the Land, and have a bredth capable to be observed. There are Fluxes in certain places, that reach into large Countries, enough to make there some apparent change; & in some of our Seas there float sometimes such bulky masses of Ice, that are far greater, than the Objects, which we are assured, we can see in the Moon. Again, we cut down whole Forrests, and drain Marishes, of an extent large enough to cause a notable alteration: And men have made such works, as have produced Changes great enough to be perceived. In many places also are Vulcans, that seem big enough to be distinguish't, especially in the shadow: And when Fire lights upon Forrests of great extent, or upon Towns, it can hardly be doubted, but these Luminous Objects would appear either in an Eclipse of the Earth, or when such parts of the Earth are not illuminated by the Sun. But yet, I know no man, who hath observed such things in the Moon; and one may be rationally assured that no Vulcans are there, that none of them burn at this time. This it is (so he goes on) which all Curious men, that have good Telescopes, ought well to attend; and I doubt not; but, if we had a very particular Map of the Moon, as I had designed to make one with a Topography, as it were, of all the considerable places therein, that We or our Posterity would find some changes in Her. And if the Mapps of the Moon of Hevelius, Divini, and Riccioli, are exact, I can say, that I have seen there some places considerable enough, where they put parts that are clear, whereas I there see dark ones. 'Tis true that if there be Seas in the Moon, it can hardly fall out otherwise, than it doth upon our Earth, where Alluvium's are made in some places, and the Sea gains upon the Land in others. I say, if those Spots we fee in the Moon, are Seas, as most believe them to be; whereas I have many reasons, that make me doubt, whether they be so; of which I shall speak elsewhere. And I have sometimes thought, whether it might not be, that all the Seas of the Moon, if there must be Seas, were on the side of the other Hemisphere, and that for this cause it might be that the Moon turns not upon its Axis, as our Earth, wherein the Lands and Seas are, as it were, ballanced: That thence also may proceed the non~appearance of any Clouds raised there, or of any Vapors considerable enough to be seen, as there are raised upon this Earth; and that this absence of Vapors is perhaps the cause, that no Crepuscle is there, as it seems there is none, my selfe at least not having hitherto been able to discerne any mark thereof: For, me thinks, it is not to be doubted, but that the reputed Citizens of the Moon might see our Crepuscle, since we see, that the same is without comparison stronger, than the Light afforded us by the Moon, even when she is full; for, a little after Sun-set, when we receive no more the first Light of the Sun, the sky is far clearer, than it is in the fairest night of the full Moon. Mean while, since we see in the Moon, when she is increasing or decreasing, the Light she receives from the Earth, we cannot doubt, but that the People of the Moon should likewise see in the Earth that Light, wherewith the Moon illuminates it, with perhaps the difference, there is betwixt their bigness. Much rather therefore should they see the Light of the Crepuscle, being, as we have said, incomparably greater. In the mean time we see not any faint Light beyond the Section of the Light, which is every where almost equaly strong, and we there distinguish nothing at all, not so much that cleerest part, which is called Aristarchus, or Porphyrites, as I have often tryed; although one may there see the Light, which the Earth sends thither, which is sometimes so strong, that in the Moon's decrease I have often distinctly seen all the parts of the Moon, that were not enlightned by the Sun, together with the difference of the clear parts, and the Spots, so far as to be able to discern them all. The shaddows also of all the Cavities of the Moon seem to be stronger, than they would be, if there were a second Light. For, although a far off; the shaddows of our Bodies, environed with Light, seem to Us almost dark; yet they doe not so appear so much, as the Shaddows of the Moon doe; and those that are upon the Edge of the Section, should not appear in the like manner. But, I will determine nothing of any of these things. When I shall hereafter have made more frequent Observations of the Moon with my great Telescopes, in convenient time, I shall then perhaps learn more of it, than I know at present, at least it will excite the Curious to endeavor to make the like Observations; and it may be, others, that I have not thought of.
In Numb. 4. Of these Papers, pag. 67. Mr. Hook had intimated, that he would shortly discover a way of his, with a Plano-convex Glasse of a Sphære of 20. or 40. feet Diameter, without Veines, and truly wrought of that Figure, to make a Telescope, that with a single Eye-glass should draw 300, 400, yea 1000 feet, without at all altering the convexity: Monsieur Auzout returns this consideration, and offer upon it, which follows:
To perform (saith he) with a lesser Object-glass the effect of a great Telescope, we must find out a way to make such an Object-glass to receive as many Rayes as one will without their being sensibly distant from one another; to the end, that by applying to it stronger Eye-glass, there may be still Beams enough to see the Object, an to obliterate the small specks and imperfections of the Eye-glass. And if Mr. Hook hath this Invention, I esteem it one of the greatest, that can be found in the matter of Telescopes: If he please to impart it to us, we shall be obliged to him; and I wish, I had a secret in Opticks to encourage him to that communication. If I did believe, that this would be esteemed one, To measure with a great Telescope the distance of Objects upon the Earth; which I have found long since, and proposed to some by way of Paradox; Locorum distantias ex unica statione, absque ullo Instrumento Mathematico, metiri; I doe here promise to discover it to him, with the necessary Tables; as soon as He shall have imparted his to me; which I will use, as he shall order me. For, although the Practise doe not altogether answer the Theory of my Invention, because that the length of the Telescopes admits of some Latitude; yet one comes near enough, and perhaps as Just, as by most of the wayes, ordinarily used with Instruments. That, which I am proposing, I doubt not but M. Hook will soon understand, and see the determination of all Cases possible. I shall only say, that if we look upon the sole Theory, we may make use of an ordinary Telescope, whereof the Eye-glass is to be Convexe: for, by putting the Glasses at a little greater distance, than they are, proportionably to the distance for which it is to serve, and by adding to it a new Eye-glass, the Object will be seen distinct, though obscure; and if the Eye-glass be Convexe, the Object will appear erect. They may be done two manner of ways; either by leaving the Telescope in its ordinary situation, the Object-glass before the Eye-glass; or by inverting it, and putting this before that. But if any will make use of two Object-glasses, whereof the Focus's are known, the distance of them will be known. If it be supposed, that the Focus of the first be B. and that of the second C. and the distance given, , and that be equal to ; for, this distance will be equal to And if you have the Focus of the first Object-glass, equal to B, the distance, where you will put the second Glass equal to the focus of the 2d Glasse will be found equal to . And if you will that the Object shall be magnified as much with these two Glasses, as it would be with a single one, whereof the Focus should be of the distance given, having the Focus of the Object-glass given equal to , and the distance given to ; the distance between the first and the second Glass will be equal to , whence subducting (the Focus of the Object-glass given) there remains ; and if this sum be supposed equal to , we shall easily know, by the precedent Rule, the Focus of the second Glass.
So far M. Auzout, who, I trust, will receive due satisfaction to his desire, as soon as the happy end of the present Contagion shall give a beginning and life again to the Studies and Actions of our retired Philosophers.
I shall onely here adde, That the Secret he mentions [Of measuring the distance of Places by a Telescope (fitted for that purpose) and from one station] is a thing already known (if I am not mis-informed) to some Members of our Society; who have been a good while since considering of it, and have contrived ways for the doing of it: Whether the same with those of Mr. Auzout, I knew not. Nor have I (at the distance that I am now from them) opportunity of particular Information.
This Experiment, having been hinted at in the next foregoing Papers, out of the Mundus Subterraneus of Athanasius Kircher, and several Curious Persons, who either have not the leisure to read Voluminous Authors, or are not readily skilled on that Learned Tongue wherein the said Book is written, being very desirous to have it transferred hither, it was thought fit to comply with their desire herein.
The Author therefore of the Mundus &c, having seen some stones reputed to be natural that had most lively Pictures, not only upon them, but passing thorow their whole substance, and thereupon finding an Artist, skilful to perform such rare workmanship, did not only pronounce such stones to be artificial, but when that Artist was unwilling to communicate unto him his Secret, did joyn his study and endeavors with those of one Albertus Gunter a Saxon, to find it out themselves: wherein having succeeded, it seems, they made the Experiments which this Industrious and communicative Jesuit delivers in this manner:
The Colours, saith he, are thus prepared; I take of Aqua fortis and Aqua Regis, two ounces ana; of sal Armoniack, one ounce; of the best Spirit of Wine, two drachms; as much Gold as can be had for nine Julio's (a Julio being about six pence English) of pure Silver, two drachmes. These things being provided, let the Silver, when calcined, be put into a Vial; and having powred upon it the two drachmes of Aqua fortis, let it evaporate, and you shall have a Water yielding first a blew Colour, and afterwards a black. Likewise put the Gold, when calcin'd, into a Vial, and having powred the Aqua Regis upon it, set it by to evaporate: then put the Spirit of Wine upon the sal Armoniack, leaving it also till it be evaporated; and you will have a Golden coloured Water, which will afford you divers Colours. And, after this manner, you may extract many Tinctures of Colours out of other Mettals. This done, you may, by the means of these two Waters, paint what Picture you please upon white Marble, of the softer kind, renewing the Figure every day for several days with some fresh superadded Liquor, and you shall find in time, that the Picture hath penetrated the whole solidity of the Stone, so that cutting it into as many parts as you will, it will always represent unto you the same Figure on both sides.
So far be, which how far it answers expectation, is referred to the Tryal of Ingenious Artists. In the mean time there are not wanting Experienced Men that scruple the Effect, but yet are far from pronouncing any thing positively against it, so that they doe not discourage any that have conveniencies, from trying.
But whether the way there mentioned will succeed, or not, according to expectation: Sure it is that a Stone-cutter in Oxford, Mr. Bird, hath many years since found out a way of doing the same thing, in effect, that is here mentioned; and hath practised it for many years. That is, he is able so to apply a colour to the outside of polished Marble, as that it shall sink a considerable depth into the body of the stone; and there represent like figures or images as those are on the outside; (deeper or shallower according as he continues the application, a longer, or lesser while.) Of which kind there be divers pieces to be seen in Oxford, London, and elsewhere. And some of them being shewed to his Majesty, soon after his happy restauration, they were broken in his presence, and found to answer expectation. And others may be dayly seen, by any who is curious, or delirous to see it.
Notice was lately given by an inquisitive Parisian to a friend of his in London, that by an Acquaintance he had been informed, that Signer Septalio, a Canon in Millan, had the Secret of making as good Porcelane as is made in China it self, and transparent; adding that he had seen him make some.
This as it deserves, so it will be further inquired after, if God permit.
An observing Gentleman did lately write out of Germany, that in Westphalia in the Diocess of Paderborn, is a Spring, which looses it self twice in 24. houres; coming always after 6 houres, back again with a great noise, and so forcibly, as to drive 3 Mills not far from its source. The Inhabitants call it the Bolderborn, as if you should say, the Boysterous Spring.
The same Person, having mentioned the many Salt-Springs in Germany, as those at Lunenburg, at Hall in Saxony, at Saltzwedel in Brandenburger Mark, in Tyrol, &c. observes, that no Salt-water, which contains any Metal with it, can well be sodden to Salt in a Vessel of the same Metal, which it self contains, except Vitriol in Copper Vessels.
He adds, that, to separate Salt from Salt-water, without Fire, if you take a Vessel of Wax, hollow within, and every here tight; and plunge it into the Sea, or into other Salt-water, there will be made such a separation, that the vessel shall be full of sweet water, the Salt staying behind: but, though this water have no saltish taste, yet, he saith, there will be found a Salt in the Essay, which is the Spirit of Salt, subtile enough with the water to penetrate the Wax.
Whereas there have lately appeared in publick some Books, printed beyond the Seas, treating of the Way of Injecting liquors into Veines in which Books the Original of that Invention seems to be adscribed to others, besides him, to whom it really belongs; It will surely not be thought amiss, if something be said, whereby the true Inventor's right may beyond exception be asserted & preserved; To which end, there will need no more, than barely to represent the Time when, and the Place where, & among whom started and put to tryal. To joyn all these circumstances together, 'Tis notorious, that at least six years since (a good while before it was heard off, that any one did pretend to have so much as thought of it) the Learned and Ingenious Dr. Christopher Wren did propose in the University of Oxford (where he now is the Worthy Savilian Professor of Astronomy, and where very many Curious Persons are ready to attest this relation) to that Noble Benefactor to Experimental Philosophy, Mr. Robert Boyle, Dr. Wilkins, and other deserving Persons, That he thought, he could easily contrive a Way to conveigh any liquid thing immediately into the Mass of Blood; videl: By making Ligatures on the Veines, and then opening them on the side of the Ligature towards the Heart, and by putting into them slender Syringes or Quills, fastened to Bladders (in the manner of Clyster-pipes) containing the matter to be injected; performing that Operation upon pretty big and lean doggs, that the Vessels might be large enough and easily accessible.
This Proposition being made, M. Boyle soon gave order for an Apparatus, to put it to Experiment; wherein at several times, upon several Doggs, Opium & the Infusion of Crocus Metallorum were injected into that part of the hind-legs of those Animals, whence the larger Vessels, that carry the Blood, are most easy to be taken hold of: whereof the success was, that the Opium, being soon circulated into the Brain, did within a Short time stupify, though not kill the Dog; but a large Dose of the Crocus Metallorum, made an other Dog vomit up Life and all: All which is more amply and circumstantially delivered by Mr. Boyle in his Excellent Book of the Usefulness of Experimental Philosophy, Part 2. Essay 2. pag. 53. 54. 55. Where 'tis also mention'd, that the fame of this Invention and of the succeeding Tryals being spread, and particularly coming to the knowledge of a foreign Ambasssadour, that was Curious, and then resided in London, it was by him tryed with some Crocus Metallorum, upon a Malefactor, that was an inferiour Servant of his, with this success, that the Fellow, as soon as ever the Injection began to be made, did, either really or craftily, fall into a swoon; whereby, being unwilling to prosecute so hazardous an Experiment, they desisted, without seeing any other effect of it, save that it was told the Ambassadour, that it wrought once downwards with him. Since which time, it hath been frequently practised both in Oxford & London; as well before the Royal Society, as elsewhere. And particularly that Learned Physitian, Dr. Timothy Clerk, hath made it part of his business, to pursue those Experiments with much industry, great accurateness, and considerable observations thereon; which above two years since, were by him produced and read before the Royal Society, who thereupon desired him, as one of their Members, to compleat, what he had proposed to himself upon that subject, and then to publish the same: the Effect whereof 'tis hoped, will now shortly appear, and not prove unwelcome to the Curious.
Some whereof, though they may conceive, that liquors thus injected into Veines without preparation and digestion, will make odde, commotions in the Blood, disturb Nature, and cause strange Symptoms in the Body, yet they have other thoughts of Liquors, that are prepared of such things, as have passed the Digestion of the Stomach; for example, of Spirit of Urine, of Harts-horne, of Blood &c. And they hope likewise, that besides the Medical Uses, that may be made of this Invention, it may also serve for Anatomical purposes, by filling, after this way, the vessels of an Animal as full, as they can hold, and by exceedingly distending them, discover New Vessels, &c: But not now to enlarge upon the Uses, the Reader may securely take this Narrative, as the naked real Matter of Fact, whereby 'tis as clear, as Noon day (both from the Time, and irrefragable Testimony of very many considerable Persons in that University, who can jointly attest it; as well as from that particular unquestionable one of Mr. Boyle and his worthy Company, who were the first Eye-witnesses of the Tryals made, that to Oxford, and in it, to Dr. Christopher Wren, this invention is due; and consequently, that all others, who discourse or write of it, doe either derive it from Him, or are fallen upon the same Devise several years after Him.
Published with License.
Oxford, Printed by A: & L: Lichfield,
for Ric. Davis. 1665.