VOL. : Latitudes 15 - 30, Inclusive This is the standard set of tables designed for marine navigation. Although there are 6 volumes in a set, only those pertaining to the latitudes anticipated need be obtained. These books are traditionally bound with hard cover. Their tabular data, being purely mathematical results, never go out of date. The latitudes listed for the Volumes work for either northern or southern hemispheres. These books are available in either Government or Commercial Editions. Because of the high prices of the Government editions, they have been reprinted as Commercial Editions at less than half the price. They are photoduplicates sized at 90% of the originals, and soft covered. They are still easy enough to read, but their smaller size of 8. 5 x 11 inches is easier to carry and store.