An Extra-long Minute

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Cook Islands 132

     Captain Cook visited the islands of Te-Au-O-Tu and Manuae in 1773 and named  them the  "Hervey Islands." In 1824 they were renamed the Cook Islands by a Russian cartographer.
     The length of a minute of latitude is always about 1 mile. A minute of a degree of longitude varies from about 1 mile at the equator to 0 at the poles because the meridians converge at the poles.
     At 1920' latitude, a minute of longitude would be .946 miles. The scale at the bottom of the map shows that the distance between 15858' and 15856'; two minutes of longitude is equal to approximately 2 miles, which is correct.

SCN 132

     The two parallels of latitude are 1920'S and 1921'S. At this latitude a minute of latitude is .99615 mile. But according to the scale it would be 2 miles,  twice the true distance, which is not correct.

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