Delays, however, took place, and it was not until 1718 that the measures, from Dunkirk on the north to the southern extremity of France, were completed.

A discussion arose as to the interpretation of these measures, some affirming that they indicated a prolate, others an oblate spheroid; the former figure may be popularly represented by a lemon, the latter by an orange.

To settle this, the French Government, aided by the Academy, sent out two expeditions to measure degrees of the meridian--one under the equator, the other as far north as possible; the former went to Peru, the latter to Swedish Lapland.

Very great difficulties were encountered by both parties.

The Lapland commission, however, completed its observations long before the Peruvian, which consumed not less than nine years.