This judicious and clearly written exposition of the meteorological remains of Posidonius builds on the fundamental work of W. Theiler and especially of L. Edelstein and I.G. Kidd. It makes more accessible Edelstein–Kidd's forbidding assemblage of fragments (collected in one volume and translated in a separate one); and supplements Kidd's narrowly focused commentary (in two further volumes). On each meteorological topic H. collects the important passages, translates them, sets them in an ample historical context and provides clear and accessible commentary. H. follows Kidd in many judgements, but in a format that is much more readable. As such, the book serves a role roughly analogous to what G.S. Kirk, J.E. Raven and M. Schofield's The Presocratic Philosophers (2nd ed. 1983) does to Diels and Kranz's Fragmente der Vorsokratiker.
H.'s presentation is remarkably Peripatetic (pp. 2–3). He sets out his material in a more or less Peripatetic order, both because Aristotle set the curriculum as it appears in later authors such as Aëtius and Seneca and because Aristotle himself recognised a similar unity among the subjects of the science in his own predecessors (Mete. 1.1.338a26). Moreover, as H. argues, the Stoics were not much interested in meteorological questions. While the early Stoics engaged in the study to some small degree, there is virtually no evidence of meteorology for the roughly 150 years between Epicurus and Posidonius. Posidonius is in lonely country, and Aristotle is his one constant companion. Finally, Posidonius is a conservative both on substantive and methodological issues, and in the face of Stoic neglect of causes he tends to prefer Aristotelian aetiologies.
H.'s purpose is not to expound a radically new interpretation of the fragments – the state of the evidence hardly allows this – though he contributes to the conversation where appropriate. The remains of Posidonius are so slight that there is often little to discuss under some of the traditional subject headings (H. summarises Posidonius’ positive contributions at p. 213). We emerge with the sense that by Posidonius’ time meteorology, with some exceptions, had run its course. In the absence of a grand thesis, H.'s narrative arc necessarily resolves into a seriatim consideration of the several phenomena. As a result, the book is more appropriate for focused consultation by specialists rather than for a cozy read on a stormy night.
Highlights of the book include a careful discussion of the measured height of (Greek) mountains and its significance for Posidonius. For we are told that clouds do not form above 40 stades from the surface of the earth (pp. 46–9). H. points out that either Posidonius deviated from the Aristotelian view that the mountain tops are the upper limit for cloud formation, or that the contemporary estimates of the heights of mountains were low. Again H. is good on close calculations on the zones as they come down from Strabo; but this discussion would have benefited from a diagram, in the absence of which the widths of all the zones are difficult to follow (p. 56).
Likewise, an interesting extension of Aristotle's view of star-tracking comets is found in the scholion to Aratus 1091, according to which a rather dense bit of air is squeezed into the aether and fixed in the aether's (if the emendation to ‘aether’ is sound) rotation (p. 79). Perhaps this is an improvement over Aristotle, who problematically compares the phenomenon to the reflection of the halo, but denies that it is caused by reflection (Mete. 1.7.344b1–8). H. follows Kidd (ii.1.492–3) in exaggerating the similarity to Aristotle's theory. He is right, however, to stress that Posidonius’ account of the changing size of the comet is an improvement over Aristotle. Posidonius also introduces a turbine effect, which is not present in Aristotle, and presumably was intended to account for the round appearance of ‘hairy’ comets.
A similar attempt at an improvement over Aristotle is found in Posidonius’ explanation of the shape of the rainbow (F 134). As Alexander of Aphrodisias pointed out (In Mete. 143.8–10), Posidonius followed Aristotle's by-then outdated reflection theory rather than the more au courant refraction. But within this basic conservatism, Posidonius realised that reflection alone is not sufficient to account for its circular appearance in a constant relative location. Although Aristotle tried to explain the circular shape of the rainbow, he seemed tacitly to assume that the shape of the cloud must be the cause. Posidonius makes this assumption explicit, by saying that the cloud is concave, the inside of a reflective hemisphere. Of course, this improvement only pushes the mystery back one step – for why should rainbow clouds only form perfect hemispheres?
It is on tides that Posidonius made the most important and original contributions based on his own observations at Cadiz. H. covers the important issues, though this section could have been more clearly laid out. From Strabo we learn of Posidonius’ three-fold distinction of daily, monthly and annual tide cycles. On the annual tide cycle, Kidd argues (II.ii.786) that Posidonius may first have believed that the summer solstice is the period of the highest tide (which Strabo reports and follows), then later corrected himself and identified the vernal equinox as the period of the highest tide period (reported by the otherwise garbled version preserved in Priscianus Lydus). To this extent Kidd is willing to trust Priscianus. H. argues that the difference between equinoctial and solstitial tides is slight and is sceptical of Kidd's ‘correction’ account (pp. 130–1). In other respects, H. is willing to place more confidence in Priscianus. He problematises Posidonius’ aetiology for tides (are they caused by winds or the expansion of seawater by the heat of the moon?), and he sides with Priscianus’ notice about tidal water forming semicircles (F 219.107–9) and interprets these, plausibly enough, as referring to bulges in the globe of water caused by the heat of the moon (pp. 134–5).
The later chapters of the book are devoted to more methodological and philosophical considerations, which tend to confirm Posidonius’ largely Aristotelian inclinations.
The most appropriate audience for the book consists of historians of science and philosophy who need a clearly organised presentation of late Hellenistic meteorology in its historical context and do not want to get bogged down in the philological minutiae of Edelstein–Kidd. As such, it is a welcome addition to the literature and only improves on re-reading. It is remarkably free of technical errors and contains an excellent bibliography.
