. Encyclopaedia : or, A dictionary of arts, sciences, and miscellaneous literature; constructed on a plan, by which the different sciences and arts are digested into the form of distinct treatises of systems ... . fince this is thecafe every where, the departure correfponding to thediflance BZ and courfe BZC, will be greater thanthe departure to the diflance oZ and courfe in the fame manner, we prove that nB is great-er than mo; and consequently, the departure corref-ponding to the diflance AB, and courfe ABL, isgreater than the departure to the diflance Ao, andcourfe AoL : Wherefore,
. Encyclopaedia : or, A dictionary of arts, sciences, and miscellaneous literature; constructed on a plan, by which the different sciences and arts are digested into the form of distinct treatises of systems ... . fince this is thecafe every where, the departure correfponding to thediflance BZ and courfe BZC, will be greater thanthe departure to the diflance oZ and courfe in the fame manner, we prove that nB is great-er than mo; and consequently, the departure corref-ponding to the diflance AB, and courfe ABL, isgreater than the departure to the diflance Ao, andcourfe AoL : Wherefore, thefum of the two depar-tures correfponding to the courfes ABL and BZC,and to the diflances AB and BZ, is greater than thedeparture correfponding to the diflance AZ andcourfe AZC ; therefore the courfe anfwering to thisfum as a departure, andCZ as a difference of latitude,(AD being the parallel of latitudes palling throughA), will be greater that the true courfe AZC madegood upon the whole. And hence the difference oflongitude found by the common rules will be greaterthan the true difference of longitudes ; and the errorwill be greater or lefs according as BA deviates more©r lefs from the direction of 3. Of determining the (hips longitude by lunar ob-fervations. Several rules for this pnrpofe have been lately pub-limed, the principal object of which fecms to havebeen to abbreviate the computations requifite for de-termining the true diflance of the fun oraflar from themoons centre. This, however, (hould have certainlybeenlefsattendedto than thcinveftigationofa folution,in which confiderable errors in the datta may produce afmall error in the required diflance. When either ofthe luminaries has a fmall elevation, its altitude willbe affected by the variablenefs of the atmofphere ;likewife the altitude, as given by the quadrant, willbe affected by the inaccuracy of the inflrument, andthe uncertainty neceffarily attending all obfervations made (a) A c/3 B fignifies the differ
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