PROBLEM IV.

To find all thofe Places which have the fame Latitude as any given Place.

All places, at the fame diftance from the equator, on the fame fide of it, are faid to have the fame latitude, or to be in the fame parallel of latitude: hence to perform this problem, bring the given place to the meridian; then turn the globe a complete revolution, and all the places which pafs under the fame degree of latitude are thofe required.

EXAMPLES.

What places have the fame latitude as Bergen ? Anf. Stockholm and Peteriburgh, nearly.

Required the places whofe latitude is the fame as Philadelphia, Jamaica, Mexico, Barbadoes, the Azores, Archangel, Cape Horn, Cape of Good Hope, London, Porto Bello, Quito, Lima, Truxillo, Hifpaniola, Baldivia or Valdivia, Potofi, Falkland Islands, Quebec, Vienna, Oporto, St. Helena, Ormus, and the Ifle of Man.

N. B. Perfons who live in the fame latitude have the fame feafons of the year, the fame climate *,

and

*It must not, however, be inferred from thefe coincident circumftances, that places fo fituated have the fame atmosphe rical temperature, as they are in fact fometimes entirely dif ferent under the very fame parallel of latitude. This difference is in fome inftances to be afcribed to the influence of moraffes, lakes, woods, forests, and large tracts of uncultivated land;

and their days are of the fame length; but these laft commence refpectively fooner or later, when compared with each other, according as the places themselves differ in their longitudes: e. g. a place fituated 15 degrees to the Eaft of another, will have its day begin an hour before, and if 15 degrees to the Weft, an hour after, this laft; and fo in proportion for any greater or lefs number of degrees.

PROBLEM V.

To find all thofe Places which have the fame Longitude as any given Place.

All places that lie under the fame meridian are faid to have the fame longitude; bring, therefore, the propofed place to the meridian, and obferve all thofe places which fall under the fame femicircle of the meridian; and these have all the fame longitude.

in others, to high or mountainous fituations. As an example we may cite part of Ruffia, which, though lying nearly under the fame parallel with Milan, Bourdeaux, and other countries and towns enjoying the most agreeable climate, is of an atmospherical temperature entirely different: and adjacent to Mofcow, the capital of the empire *, which is fituated under the fame parallel with Edinburgh, the whole country was covered with fnow in the middle of April, notwithstanding the winter had been mild and the fpring uncommonly early in Great-Britain. Again, Newfoundland, which lies under the fame parallel with the Northern part of France, is usually covered with fnow five months in the year.

* Peterburgh is ftyled by the Ruffians "The Place of Refidence," from being the ufual refidence of the latter fovereigns.

EXAMPLES.

What places have the fame longitude as Buenos Ayres-Anf. The Caribbee Ilands, the S. W. part of the Ifland of Newfoundland, and Cape Breton.

Required the places whofe longitude is the fame as Peterburgh, Genoa, the Philippine Islands, the Pelew Iflands, Amboyna, Madras, Lisbon, the Sandwich Islands, the Society Ilands, the Friendly Iflands, New Zealand, Bombay, and Juan Fernandez.

N. B. Perfons having the fame longitude, who are fituated in the torrid, or either of the temperate zones, and whofe latitude, of course, does not exceed 664 degrees either North or South, have always fimilar periods of the natural day, or, in other words, of that fpace of time (24 hours) which the earth takes to perform its diurnal revolution. The light or darkness at thofe times will, however, vary according to the refpective fituations of the places. For inftance, a perfon refiding at the equator, under the fame meridian with London, has his artificial day terminated at fix o'clock, even at our fummer folftice or longeft day; whereas to an inhabitant of London the fun does not then fet till paft eight. The difference is ftill greater to perfons in oppofite hemifpheres; the longest day with the one being the shorteft with the other, and vice verfa: yet will the hour be precifely the fame if they are fituated under the fame meridian; i. e. it will be mid-day, or one, two, &c. hours after or before that period with the one, when it is fo with the other.

Places

Places which lie under oppofite meridians, have their noon, and every other hour of the natural day, at oppofite times. Thus when it is mid-day at London, it is midnight to all thofe places which are under the oppofite meridian.

PROBLEM VI.

To find the Difference of Latitude between any two given Places.

Bring the propofed places to the brazen meridian, and note their refpective latitudes. If they are both in the fame hemifphere, fubtract the latitude of one from the other, and the remainder will be the difference: but if they are fituated on different fides of the equator, the fum of their latitudes will be the difference of latitude required.

EXAMPLES.

What is the difference of latitude between Madrid and Petersburgh ?-Anf. 20 deg.

What is the difference of latitude between Cape Verd and St. Helena ?-Anf. 30 deg.

Required the difference of latitude between London and Copenhagen; Archangel and Damafcus; Bombay and Goa; Pekin and Canton; Aftracan and Schiras; Baffora and Mocha; North Cape and the Cape of Good Hope; Stockholm and Mexico; Philadelphia and Jamaica; Quebec and Panama; Porto Bello and the Streights of Magellan; Tobago and Sierra Leona; Bermudas and Jamaica; Cape Verd and St. Helena.

To find the Difference of Longitude between any two Places.

As all places that lie under the fame meridian have the fame longitude *, fo all places that lie under different meridians, have different longitudes and this difference may be either Eaft or Weft, confequently the difference of longitude between any two places, is the distance of their meridians from each other, measured at the equator. Find, therefore, their refpective longitudes; and if both places are fituated on the fame fide of the firft meridian, fubtract the longitude of one from the other, and the remainder is their difference but if they are fituated on oppofite fides of the meridian, add their longitudes together, and the total will be the longitude required.

EXAMPLES.

What is the difference of longitude between Burfa and Cape Rafalgat ?-Anf. go deg.

What is the difference of longitude between Petersburgh and Vera Cruz? Anf. 130 deg. nearly.

Required the difference of longitude between Cork and Canton; Rome and Calcutta; Pico and Botany Bay Vera Cruz and Siam; Quito and Cape Comorin; Seville and Rhodes; Oporto and Bofton; Cape Florida and Borneo; Gibraltar and Barcelona; London and Bourdeaux; York and Mount Hecla; Vienna and the Azore Iflands; Malftrom and Lisbon.

*See Problem V.

PROBLEM