Scope and Contents
Two straightforward records of planetary eclipses, but meant, on palaeographic evidence, to be kept with a draft and a fair copy of a subsequent Philosophical Transactions of the Royal Society article [Vol. XXIV, No. 293, for September-October 1704, p1704] about the Cassini curve, a model of how a periodic comet probably orbits. Folding and fading of these documents suggest that they were inserted not long after David Gregory generated his index of Quarto A (which he drew up around 1700). [28.1], seems to have enfolded [28.2], which enfolded [28.3], which enfolded [28.4]. ([28.4] goes with [28.3], being merely the calculations for two of the curves in the first figure.) Another draft of this article may exist, loose, in Folio B (see note 3). Editorial basis for inclusion of this article on comets with item 28, about planets, may be Gregory's first exposure, in 1698, to Cassini's earlier suggestion that the curve might describe a planetary orbit (see note 4). Gregory was a theoretical astronomer, who rarely observed things; the 1697 measurements were then an important, if minute, data set from which to prove or disprove the suitability of the curve for planets' trajectories. The article's point is finally to refute Cassini, though not obviously on the strength of these particular observations. The last page, only a quarter of a quarto, may not even go with this batch of papers, though it matches them better than the next item on Gregory's index on content and palaeographic clues. It is a short bibliography of works on gravity, for the most part, partially cited.