MATHEMATICIAN, GEOGRAPHER

Life
Marinos was a native of Tyre, but spent most of his life in Rhodes. He was one of the first of the mathematical geographers, and is mentioned by Ptolemy in his "Guide to Geography" ("Marinos the most recent of us"). Although his work - which included a description of northern Europe - has most unfortunately been lost, it was praised by Ptolemy and cited by the Arab geographer al-Masoudi.


Work
Marinos drew a map using a cylindrical projection and "meridional parts" (linear length of one minute of longitude), which have an application in navigation. He was the first to use the "Meridian of the Isles of the Blest" (Canary Islands, at the western edge of the known world) as the starting-point for the measurement of longitude, and the parallel that passes through Gibraltar and Rhodes (36?) as the starting-point for the measurement of geographic latitude. The meridians and the parallels of latitude were thus presented as two sets of straight lines perpendicular to one another. This produced a system of co-ordinates that allowed every place on earth to be positioned accurately on the map, by its latitude and longitude. Marinos divided the globe into "time zones" (hourly equatorial intervals ), assembled data on the geography of different places, and drew a map that for the first time ever gave an accurate image of the known continents and countries.

Marinos wrote a "Geography", and in 114 AD composed a "Corrected Geographical Tables", which Ptolemy used as a basis for his geographical work. He made a study of meteorology, and particularly of the winds. His work influenced cartographers until the end of the Renaissance period. He held to the geocentric system. He agreed with Posidonius that the parallel that ran through Rhodes was 32,400 km (180,000 stades), very close to the real value of approximately 32,000 (4/5 the length of the equator).

"Rhumb lines": These are still used today in navigation. Marinos used them to calculate the length of the Inhabited World. Ptolemy credits Marinos with the elaboration of the related theorems.

According to Marinos, the Inhabited World:

1) Extended from the Island of Thule (Iceland) to the Ethiopian region of Agisymba, and from the Isles of the Blest (Canary Islands) to Shera (China) and Cattigara.

2) 'Ultima Thule' was the northern extremity of the known world.

3) The land of Agisymba was beyond the winter solstice.

4) Marinos used the prefix "anti" to define opposite-lying places (e.g. Rion/Antirion). He was the first to use it, and the first to introduce the terms Arctic / Antarctic Circle, Temperate / Antitemperate Zone, Inhabited / Anti-Inhabited World, terms that are still in use today.

5) The Inhabited World extends as far as the 225th parallel of longitude (Ptolemy thought it extended to the 180th).

6) The distance from the Isles of the Blessed to Ierapolis on the Euphrates given by Marinos was adopted by Ptolemy.

7) The Inhabited World occupies half of the Northern Hemisphere, and has the shape of an out-flung mantle (development of a truncated cone).

8) The breadth of the Inhabited World = 31500 stades.

9) Marinos calls the southern hemisphere Ethiopia Rapta, and mentions Cape Verde south of the Equator as a place Greek sailors had reached. The distance he calculates at 27800 stades, and he places Agisymba, Ethiopia Rapta and Cape Verde on the 24th parallel of southern latitude.

He used biogeographical data to solve geographical problems, and his naval chart is still in use today.