The Newton's Alchemy post (Ralph Luker at Cliopatria has a deeper discussion of Newman's work) has left me thinking about Berkeley's interest in tar-water. While not quite as interesting as Newton's alchemy, it would be great if there were work done on this point. The project actually has quite a bit of potential. The basic historical facts seem to be these:
1. Berkeley discovers tar-water being used as a folk remedy while in America waiting for the grant to build a College in the Bahamas. (The grant, of course, never materialized, being re-appropriated to buy presents for a member of the Royal Family.) It is not (as far as I can recall) very clear how he came across it, but he later seems to be fairly knowledgeable about different variations of its use in America, so must have researched. This would be in keeping with his character; we know from his journals in Italy that he did this sort of thing -- in Italy he researched the tarantula (both the spider and the dance, and how they were connected in folklore).
2. As Bishop of Cloyne, a very poor Irish county, he makes research and dispensation of tar-water a major priority. (From what I understand this wouldn't be very surprising; because he had book-learning and was a clergyman, he would likely have been the person to whom the poor in the county would have turned for help in medical matters when nothing else seemed to work.) He keeps trying to tweak the procedure for optimum effect; but he's heartened by its apparent success.
3. He writes several works advocating the use of tar-water and thereby becomes involved in controversy with the apothecaries of the time. Berkeley's own assessment of the situation is that they are protecting their purses: apothecaries' wares are expensive, and tar-water is very cheap (given Berkeley's lifelong and almost saintly interest in helping the poor, this was undoubtedly one of the recommendations of tar-water), and, if its use spreads, it would put the apothecaries out of business. In Siris, Berkeley connects his interest in tar-water with his other philosophical interests, and attempts to fit it into the the alchemical work of Boerhaave and others (including Newton!).
4. The use of tar-water spreads; it is used both as a tonic (cf. its brief appearance near the beginning of Dickens's Great Expectations) and (this I think is particular interesting) as a substitute for 'strong spirits', both of which were originally advocated by Berkeley.
The scientific fact seems to be that tar-water consists of ordinary water, plus minute amounts of carbolic acid, acetic acid, and wood creosote (which is not to be confused with the carcinogenic tar creosote). What I find intriguing about this is that all three of these substances have antiseptic properties. So, taking all these apparent facts together, we would have the rudiments of a rather elaborate interdisciplinary project that would require (in all cases assuming the relevant work hasn't been done already):
* historical work on folklore in order to find out whatever can be determined about the status of tar-water as a folk remedy in the 17th and 18th centuries;
* historical work on the situation of the poor in Cloyne in the 18th century;
* scientific work on tar-water to clarify the situation (e.g., by drinking large quantities of tar-water every day was Berkeley genuinely helping himself, or poisoning himself, or something in between?) Some work has been done on wood creosote (see, for example, this paper; and this one, and the properties of acetic acid and carbolic acid (a.k.a., phenol) are, I think, fairly well known. But I don't think there's been anything that looks particularly at the sort of dilution of these substances one would get in tar-water. As I noted above, all three substances have antiseptic properties (Lister used carbolic acid as his primary antiseptic), and it would be interesting if it had the potential to improve water quality or as a mild antiseptic when used as a wash (one of the uses Berkeley advocates); but given how diluted they would have to be this might not be possible (on the other hand, carbolic acid is no mild antiseptic, since a stronger solution is still used, from what I understand, as part of the process for denaturing biological weapons).
* historical work on Berkeley's own researches (we have, in addition to his published works, a number of letters, although for the most part our information on this point is rather obscure);
* historical work on the alchemical tradition to which Berkeley appeals in works like Siris in his attempt to find an explanation for tar-water's apparent properties as a panacea;
* historical work on the spread of tar-water use do to Berkeley's efforts, in particular its role in early attempts to deal with (for example) the Gin Problem.
This is quite a hefty potential research project; I'll have to think about it more. In particular, I think I'll need to look into the question of how much work has actually been done in each of these areas (fairly little, I would imagine, but there's bound to be something relevant in several of these areas). Interesting food for thought; as I said, I'll have to think about (and research) it more. Naturally, if any readers of this blog happen to be experts on the properties of carbolic acid, or on American folk remedies in the 18th century, or anything else, I'd be interested in your thoughts.