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[Page 19]
repeat the Angles, to prevent the hazard of an irreparable Error. A little Practice will make this Operation familiar; & the second Gun may then perhaps be dispensed with
It is obvious, that is Method of obtaining a Base will suit as well or may be even more necessary where the Coast lies very oblique to the Meridian - It may also be practised on Points of Land that are not too far distant, to allow of the Report of a Musketoon or Blunderbuss being heard but perhaps it would be imprudent to trust it in very short Bases
Hadley's Quadrant is so very useful And commodious a surveying Instrument at Mast Head (when seconded below by a Knights Compass to take the bearing of some Remarkable Land, in view from the Deck, for an Observation Line) that altho so very obvious to every Surveyor we cannot avoid Recommending the use of it in the strongest Terms. In the present Case the Sphere of Observation is much enlarged: for a flat Point or Island; a rock, or a shoal may thus be set from Masthead & lines of Bearing to them secured which lines by the Objects not coming in sight from the Deck until the direction became too oblique, might never occur below nor is the Hadley less useful on Deck by preventing those Delays & disappointments which the Compass often occasions by its vibrations - One Line taken with Accuracy by the Compass will then Serve to Reduce all the Angles of the Hadley to Bearings of the Compass: & when Promptitude is required more Hadleys than one may be employed. Another most valuable