Don’t try this at home: Berkeley and tar-water

For Tom Stoneham, Peter West and Clare Moriarty 

Three hundred and thirty-six years ago today, George Berkeley was born in Thomastown, Co. Kilkenny. One year ago today, the first major Covid19 restrictions for Ireland were announced. Living in a time of Covid perhaps gives us a new appreciation of the world in which Berkeley lived. Disease was a constant danger and deaths were common particularly among the young: Berkeley’s contemporary Francis Hutcheson died of a fever in Dublin in 1746, with seven children predeceasing him. Three of Berkeley’s four children born in Cloyne where he was bishop predeceased their father.

Disease was rampant and medical infrastructure close to non-existent in the Cloyne of Berkeley’s time. This was particularly the case in the years following the winter of 1739/40, the Great Frost, an extended period of extreme cold that froze the potatoes in storage pits. Loss of that food, combined with spells of cold and dry weather in the months afterwards causing crops to fail, led to the deaths of between 13% to 20% of the Irish population. No wonder the period was called Bliain an Áir, the Year of Slaughter.

Connolly's Folly
The Obelisk, built in Kildare in 1740 as famine relief works. Ilja Klutman/Wikimedia, CC BY-SA 2.0.

Famine went hand-in-hand with sickness, with the starving people unable to fight off disease and unable to afford whatever medical help was available. Berkeley had heard of tar water in his time in the American Colonies; he had used it for his own health problems. While distributing £20 a week among the poor of Cloyne he also advocated this substance as a potential cure for infections1.

In his later treatise Siris (1744), ironically the best known and best selling of his works in his lifetime, Berkeley describes how tar-water is made2:

In certain parts of America, tar- water is made by putting a quart of cold water to a quart of tar, and stirring them well together in a vessel, which is left standing till the tar sinks to the bottom. A glass of clear water being poured off for a draught is replaced by the same quantity of fresh water, the vessel being shaken and left to stand as before. And this is repeated for every glass, so long as the tar continues to impregnate the water sufficiently, which will appear by the smell and taste. But as this method produceth tar- water of different degrees of strength, I chuse to make it in the following manner : Pour a gallon of cold water on a quart of tar, and stir and mix them thoroughly with a ladle or flat stick for the space of three or four minutes, after which the vessel must stand eight and forty hours that the tar may have time to subside, when the clear water is to be poured off and kept covered for use, no more being made from the same tar, which may still serve for common purposes.

In a letter dated 3rd December 1744 to the French translator of Siris, D. W. Linden, Berkeley explains that he did not see tar-water used in the part of America where he was but had heard of its use against smallpox in Carolina. That appears to be the origin of the first recipe, with the second version Berkeley’s own, a more standardised and palatable tar-water. Berkeley was not sure of its origin, but believed it a native remedy.  (Many thanks to Clare Moriarty for pointing out this letter.)3

Mr and Mrs Joe, Great Expectations. Woodcut scanned by Philip V. Allingham, courtesy of Victorian Web.

In Siris Berkeley describes using this as a treatment for smallpox, where a family of seven children all survived the disease except one who “could not be brought to take it”. Little wonder that poor child rejected it: even in Berkeley’s improved version it tastes foul. In Great Expectations (chapter two) Charles Dickens portrays his unpleasant character Mrs Joe administering it as a restorative cum punishment for Pip and Mr Joe.

Berkeley outlines a number of diseases which he believes tar-water has successfully treated and describes how he believes the substance assists the body, for example: “the particles of tar are not only warm and active, they are also balsamic and emollient, softening and enriching the sharp and vapid blood, and healing the erosions occasioned thereby in the blood-vessels and glands” (page 26). He believes the various qualities of tar-water mean that it can replace most medicines (and to be fair, it is safer than at least one he cites, mercury.)  

It is not much fun to take, but it might be fun to make: Berkeley notes that colder water or less stirring makes the tar-water weaker; the converse makes it stronger. It should be, he says, no lighter than French white wine and no darker than Spanish white wine (p. 5). Checking the dilution using this comparison method (while not wasting the open wine) is not the worst way to spend an evening.

The 1747 edition of Siris has appended to it a number of accounts of cures laid to the credit of tar-water. Berkeley was mocked and later criticised for his advocacy of the concoction4, though his biographer defends him: “his claims for the substance were modest; he found it good for alleviating his own health problems, and found that others reported similar results. Moreover he was moved to take some form of action in the face of widespread ill health in Ireland.” Not merely medical help either, but spiritual: the book not only aimed at advocating tar-water as a panacea and providing scientific background to justify belief in its efficacy, but “to lead the mind of the reader, via gradual steps, toward contemplation of God” 5

On Tar (a poem appended to some coppies of the 2nd 1744 edition of Siris
From A. A. Luce “Unpublished Berkeley letters”, p. 160.

Siris had influence on at least one man well after tar-water’s popularity as a panacea faded. T.T. Henn, writing of Yeats’ reading of Berkeley says, “There are whole passages in this last curious disquisition [Siris] that slides so easily between tar-water, Neo-platonism, chemistry and metaphysics, that may well have served Yeats as sources.” 6. Jeffares, also writing on Yeats’ interest in Berkeley, refers to an article Yeats probably read by (the Kantian) J. H. Bernard in Dublin University Review (March 1885) which includes the tall tale that the Tipperary man Cornelius Magrath who reached 7ft. 10 inches (and whose bones now reside in Trinity College) was raised on tar-water in Berkeley’s house. 7

The philosopher John O. Wisdom suggested George Berkeley’s interest in tar-water reflected a life long concern with purity and contamination (for more see this post). Yet perhaps from our perspective mid-pandemic, we can identify instead a very human urge to find something, anything, to ward off a disease that seems almost impossible to prevent. While we sympathise with it, we should also take it as a warning: not every potion that people report working, from tar-water to elderberry, actually does.

Featured Image: ornament on page 9 of “Siris : a chain of philosophical reflexions and inquiries concerning the virtues of tar water, and divers other subjects connected together and arising one from another” (1744)


  1. Paul O’Grady (2011) “Berkeley, George” Dictionary of Irish Biography (ed.) James McGuire, James Quinn. Cambridge, United Kingdom: Cambridge University Press, 2011. ( )
  2. George Berkeley (1747) Siris: a chain of philosophical reflexions and inquiries concerning the virtues of tar water (London re-printed : for W. Innys ( )
  3. A. A. Luce (1932) “Some Unpublished Berkeley Letters with Some New Berkeleiana.” Proceedings of the Royal Irish Academy. Section C: Archaeology, Celtic Studies, History, Linguistics, Literature 41, pp. 141-61. This letter, in French, pp. 160-161.
  4. For more detail see Scott Breuninger (2009) A Panacea for the Nation : Berkeley’s Tar-water and Irish Domestic Development”Études irlandaises, 34.2, 29-41.
  5. Lisa Downing (2020) “George Berkeley”, The Stanford Encyclopedia of Philosophy (Spring 2020 Edition), Edward N. Zalta (ed.), ( ).
  6. T. R. Henn (1965) The Lonely Tower: Studies in the Poetry of W. B. Yeats London: Methuen, p. 44
  7. A. N. Jeffares (1984) A New Commentary on the Poems of W. B. Yeats, Palgrave Macmillan, p.281
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