Notes to an extended conversation with Fatio de Duillier, fellow enthusiast of Newtonian science at Oxford, and especially important to Gregory between December 1691 and May 1694, when he was cut off from direct contact with Sir Isaac Newton, whom he had offended in a published commentary on his 'abrumpent' mathematical series. Topics include magnetic attraction, refraction and colour, and movement of solids through fluid, with anecdotal remarks by de Duiller about ships, tides, and the French. He mentions a remarkable clock recently made for the Queen. More significant are his lines on how true arches must contain the catenary curve, a fact known generally since 1676, but which first appears in Gregory's corpus here. (Newton subsequently proved it for him, after they had reconciled.)