To mine approved Friend Andro Hart.  
MASTER heart, being at KINGHORNE, bearing company to my dear and sickly Nephew, who is come thither to crave help from this recently laureate Master Doctor, the newfound, much celebrated Well, I have penned a little Discourse, containing in a Letter To my Lord Chancellar, the Nature and Effects of this Water. But I am wonderfully importuned, either writing or diting Copies of the same. For the which cause I send to you, as to a Common Father of Letters, the principal piece: that you may give it the Cognissance of your Characters, and a patent Passport under the Seal of your Press. So constrained to cut short, by the clamour of Mariners calling to the Tide, I take my leave at Leith this 8. of August, anno 1618.  
Your most affectionate friend BARCLAY, Doct. Med.   

THE NATURE & EFFECTS OF THE NEWFOUND WELL AT KINGHORNE: Declared by William Barclay, Master of Arts and Doctor of Physic, AND Written in a Letter to my Lord the Earl of Dumfermeling, and Chancellar of Scotland.  
EDJNBURGH, Printed by Andro Hart, ANNO DOMINI 1618.   

TO MY VERY HONOURABLE LORD, My Lord the Earl of Dumfermeling, and Chancellar of Scotland.  
MY LORD,  
I Know how little leisure the Affairs of this Kingdom do afford to your L. and I know how large a Discourse the Argument of this Letter doth minister: Therefore I shall not distract your L. busied attension; neither shall I extend this purpose, but according to your L. intelligent judgement I shall contrive an obscure and intricate subject to a compendious narration.  
This lately found, and newlie-knowne, tootoo long unknown Well, Si fama didicit jam non mentiri. This Well is so blazed abroad, and our Physicians, not without cause, are so loath to open their minds concerning the same, that I, emboldened both by your L. countenance and Understanding, have taken the hardiness to break the ice, and show to your L. so much as I can perceive, touching the causes and nature of this Water, and of the effects and virtues thereof, that the rest of my more learned Colleagues may be encouraged to die their exercised Quills in this wholesome Liquor.  
IT is a mixed water by the continual flowing thorough a metal, from whence it hath contracted a spiritual energy, and a certain Mercurial subtle substance: To be short, The metal which hath communicated force and efficacy to this water, is Tin. The reasons of my conjectures are taken from three heads: 

1. From the substance of the water:  
2. From the effects thereof:  
3. And from the adjacent circumstances.   From the water itself are many pregnant reasons: As that the water being a compound, and mixed body, it carrieth no savour or taste of any thing, but of pure water; which argueth none other metal but Tin: For any other Mineral, or Semi-minerall, except Gold and Silver, would bewray itself, by taste or colour. But Gold it is not, neither is it Silver, which I affirm by the effects: For all Physicians, both Dogmatickes and Spagyrickes, receive Gold and Silver amongst their cordial Medicamentes, and not amongst the Nephritickes: But this water is by experience Diuretic, and asswadgeth evidently Nephriticke dolours, washeth the ureteres, and the bladder: which effects the Paracelsians attribute to Saturn. I need not to draw the consequent which willingly follows the premises. More, this water being distilled, or exhaled, leaveth in the bottom of the Alimbecke a Salt unsalt, that is, a matter white like Chymik salt, which is unsavoury, and somewhat inclining to sweet, much like to the matter which the Alchimistes draw from Tin, and call it Saccharum Saturni.  
Now secondly, from the effects I prove it to be Tin, Because the whole furnace of Paracelse keep as a great secret in their Philosophical extractions, That Saccharum Saturni, that is to say, the salt of Tin is the only special thing to cure an ulcere in the kidneys, because it is diuretic, and so carrieth to the afflicted part, and then it is detersive and drying, which qualities do cure an ulcere, and which qualities we find in this water.  
lastly, from the adjacent circumstances, we reason this way: It is not unprobable, that there should be Tin in that part, because it is a metal familiar, and domestic to this Island, the best of Europe being found in ENGLAND. And the channel of the water, in that cleft of the Rock where it floweth, hath participated of the tincture of Tin, as appeareth to every one that beholdeth: The Rock it self notwithstanding being as it were embroidered, and pessimented with white laces of clear and crystalline stones.  
AS Towards the effects of this Water, There are two things to be said, 1. What it might do, being Physicallie used: 2. And what it hath done, being Vulgarly abused. For the first I will superceede, because I am loath, at this time, to trouble your Lordship for the other.  
This water is experimented to be very aperitive, and serveth very much for the washing away of Sande, being taken in such quantity as maketh a speate: (Neither hath it been found that an exceeding great quantity of it hath done any harm) And it bringeth down little stones from the kidneys, and expelleth them also from the bladder. Yet it is not tried to have force to diminish or demolish a conformed and solidated stone in the bladder, albeit it hindereth the intolerable dolors of the pitiable gravels, and quencheth the burning heat of their water, and causeth them make water without painful dropping. It is very detersive, for the which quality it looseth the belly of some. It is also very drying, and in this respect it bindeth the belly of most part of Drinkers: as we remark the same accidents fall out in the use of Milk: For the croudy part bindeth some, and the serous or wheyish part looseth others. Now joining these two properties together, to deterge and to dry, it maketh a sovereign remedy for all internal ulcers, also for this detersive quality, it is good for the sight, because it taketh away all clouds or blots, which effuscate or dim the Cornea tunica, and causeth the Species intentionales to pass more purely & clearly to the humour crystalline.  
I add thus much more, That there is not a more dainty Fairde for Ladies: no not Oleum talci, which is so curiously ever sought, and never found. It plaineth & polisheth their faces, and taketh away all blots and furrows, and leaveth no frumples in their Skins, with greater security and honour, than the venomous Sublimatum, or Cerussa, which they so frequently abuse, Because this water hath the most spiritual operation of Mercury, quintessenced from the Tin: which I confirm by two reasons: The one is, because it is sudorific, & procureth sweat in abundance, being drunken some number of days consequently. The other is, because the temperament of it is hot, albeit it be actually cold. The heat appeareth, in that it procureth to the eyes first a smart, and next a great itch.  
Lastly, this is a sovereign and unicke remedy for that disease in Women, which they never acknowledge to be a disease, while it be almost past remedy: and more than a disease, when Physicians have none help, but only sorrow to hear their complaints, and the regrate of their lamentable negligence. So ceasing to prosecute this warsh matter of water, I will never cease to continue  
Your L. most humble and obedient servitor BARCLAY, Doct. Med.