Editing Gerardus Mercator (section)

===Globes and instruments===
The globes by [[Gemma Frisius]] and Mercator are discussed in Volume 3 of the History of Cartography (Cartography in the European Renaissance).{{sfn|Woodward|1987}} Chapter 6: "Globes in Renaissance Europe" by [[Elly Dekker]]. Chapter 44: "Commercial Cartography and Map Production in the Low Countries, 1500–ca. 1672" by Cornelis Koeman, Günter Schilder, Marco van Egmond, and Peter van der Krogt. The definitive work is "Globi neerlandici: the production of globes in the Low Countries" by Peter van der Krogt.{{sfn|van der Krogt|1993}}
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*'''1536 Gemma Frisius terrestrial globe.'''

::Wholly devised by Frisius who invited Mercator to engrave the text. The only extant example is part of the Schmidt collection held by the [[Globe Museum]] ([https://web.archive.org/web/20160630094440/http://www.onb.ac.at/ev/globe_museum/globe_history.htm website]) of the [[Austrian National Library]]. Another example held at the Gymnasium Francisceum of [[Zerbst]] in eastern Germany was destroyed in the Second World War, but there is a full description in Stevenson.{{sfn|Stevenson|1921|p=102}}

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*'''1537 Gemma Frisius celestial globe.''' [http://prints.rmg.co.uk/art/496943/celestial-table-globe Image] {{Webarchive|url=https://web.archive.org/web/20170202001440/http://prints.rmg.co.uk/art/496943/celestial-table-globe |date=2 February 2017 }}
::The only known example is held by the [http://www.rmg.co.uk/ Royal Museums Greenwich] (formerly the National Maritime Museum). On this globe Mercator's name appears on equal footing with that of Frisius. The globe is also described in Stevenson.{{sfn|Stevenson|1921|p=102}}
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*'''1541/1551 Terrestrial and celestial globes'''
::Over twenty pairs of large (420mm) globes are still in existence. Both of the globes and their un-pasted gores may be examined in high resolution.{{efn|The terrestrial and celestial globes may be examined in high resolution at the [http://hcl.harvard.edu/libraries/maps/exhibits/mercator/main.html Harvard Map Collection] {{Webarchive|url=https://web.archive.org/web/20120817121654/http://hcl.harvard.edu/libraries/maps/exhibits/mercator/main.html |date=17 August 2012 }}}}{{efn|The gores for both Mercator globes held by the Bibliothèque Royale (Brussels) have been published in facsimile with a preface by Antoine de Smet ({{harv|Mercator|Smet|1968}}. High resolution images are available at the [http://nla.gov.au/nla.obj-233256665/view National Library of Australia] (click on Browse).}} A full description of the globes may be found online in Stevenson.{{sfn|Stevenson|1921|pp= 124–135}} 
::The terrestrial globe is significant in conjecturing that North America is separated from Asia, unlike the globe of Monachus. Another feature, the shape Mercator ascribed to ''Beach'' and ''Maletur'', later gave rise to speculation that the north coast of Australia had been visited in the early sixteenth century.{{sfn|Crane|2003|loc=Chapter 13|p=346, n14}}{{sfn|King|2017}} An inscription on the globe promises: "Where and for what reasons we have departed from the editions of others, Oh Reader, will be pointed out in our booklet".{{efn|''Vbi et quibus argumentis, Lector, ab aliorum desciverimus aeditione libellus noster indicabit.''}}
::Mercator also added a feature of special value to seamen: from the numerous compass or wind roses he drew rhumb lines rather than great circles. The rhumb lines correspond to constant sailing directions but on the spherical globe they appear as spirals. The globe was manufactured in great numbers but it was never updated. The celestial globe was up to date in using the information provided by Copernicus.{{sfn|Crane|2003|loc=Chapter 16 |p=170}}