CHAPTER XXIX.

[Sidenote: A narrow Ditch the Duke of Bridgewater’s Canal.]

Section 166. In a few Minutes, a Side-Break throu’ the Clouds discovered a long ill-formed narrow Line or Ditch, something less than a Foot in Breadth, extending several Ways: and which from its Proximity to Places that were known, and coming into View; viz. the Country about Norton and Halton-Castle; proved to be the Duke of Bridgewater’s Canal.

[Sidenote: A Glympse of Runcorn Gap.]

+Suddenly+ came in Sight the _spacious_ +open+ of the Mersey above Runcorn Gap: which appeared of a +ruddy+ Colour, and _very_ near: as if the Balloon had again _felt_ the Influence of the _River_.

[Sidenote: _Balloon-Geography_ first suggested for _Maps_.]

167. A new System, that of _Balloon-Geography_ here suggested itself: in which the Essentials of _Proportion_ and _Bearings_ woud be far more accurate, than by the present Method, both for _Maps_ and _Charts_, viz. To make Drawings by +sight+, from the Car of a Balloon with a _Camera Obscura_, aided by a Micrometer applied to the under Side of _the transparent_ Glass.

[Sidenote: Air presumed to be warm with South-West Wind long continued.]

The Season proper for such an aironautic Expedition, would be _any_ _calm bright_ Day: the Wind having blown from the South West Quarter, for some Days before, which is _frequently_ the Case: the Air, at _such_ Conjuncture probably remaining +warm+, to the Height of a Mile or more, unless in the very Midst of Winter.

[Sidenote: Balloon Geography for _Charts_.]

168. And particularly for Charts, which in a _maritime_ Country are _most_ useful: as Balloons have an extraordinary Predilection to become _stationary_ over Channels and Rivers; altho’ a very _strong_ Gale of Wind, shoud continue the _whole_ Time to blow in an horizontal Course directly +under+ the Balloon.

[Sidenote: Balloon in a Calm with a _strong_ Wind _below_.]

Of which Event the Writer of this Account was an _Eye-Witness_, in the Case of Mr. Lunardi: who was _detained_ above 20 Minutes over the _broad Bend_ of the River Mersey, near Ince, in Cheshire, the Day he _landed_ between Tarporley and Beeston-Castle, ascending from the New Fort at Liverpool. He quitted his Station by the Escape of Gass, and descended into the _Stream_ of Wind, which continued as _violent_ as before.