The Object that next drew his Attention, _while ascending_, was the Overley Turnpike-Road, which is remarkably wide, (resembling the Emilian Way across the Atrian Fens, between Bononia and Ferràra in Italy) raised over Saltney Marsh, leading to North-Wales and Holyhead: composed of Sea-Sand cast up above high Water Mark. This appeared like a narrow Foot-Path well trodden, of a _white_ Colour, and strait as if drawn by a Line. [Sidenote: River Dee red.] 44. Nothing however raised his Curiosity more than the Change in Colour of the River _Dee_, Avon ddû, (i.e. _Thee_) which in the British Language signifies the _black River_, from the Appearance of its Waters, when seen from an Eminence running in their deep Channel between the Mountains of Wales; but which glides by Chester with a Silver Stream. This River,—Thanks to the cool Climate; not like the _green_ Mincius of Virgil!—had now acquired the unvaried Colour of _red Lead_. Nor coud he discover even the Appearance of Water; but merely that of a _broad red_ Line, twining in Meanders infinitely more serpentine than are expressed in Maps. [Sidenote: Cause of the Change conjectured.] Whether the Change arose from the Transparency of its Waters, when seen at the Height which was _apparently_ 7 Miles, _as will be noticed hereafter_, though the Barometer made it scarcely a Mile and Half, is uncertain. He was at first inclined to think, that the Rays, having suffered a double Refraction, were reflected to the Eye, from the reddish Sand which forms their Bottom, tho’, at the Depth of 7 Yards at an Average, above the Cause-Way, or _artificial_ Cascade near Chester Bridge: or possibly the Water of Rivers when seen at a certain Distance, may act as Water composing Clouds when view’d from below, at a certain Height and Angle; reflecting only the _red_ Rays: the rest being refracted, or absorbed. The Colours of Objects shone more brilliant and lively at that amazing Height, than if seen on a Level with themselves. Nor did the Eye seem to want the Aid of Glasses: as every Thing, that coud be seen at all, was seen distinct. [Sidenote: The City of Chester _blue_.] 45.The _Redness_ of the River Dee was curiously contrasted by a Change equally novel but more pleasing, in the Colour of the City of Chester, when seen directly from above, on a Scale not larger than the Plan of it, in Burdett’s Map. The Town was entirely _blue_. The highest Buildings had no apparent Height: their Summits were reduced to the common Level of the Ground. Nor was the Cathedral distinguished; nor any Tower or Spire discerned. The Whole had a beautiful and rich Look; not like a Model, but a coloured Map. The Roofs of all the Houses appeared, as if covered with _Lead_, in the most elegant Taste.