# A New and Improved System of Mnemonics/Chapter 6

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CHAP VI.
GEOGRAPHERARY.
This most important science, as far as respects the relative situation of places, is easily attained by our method. One may carry a Map of the World in the mind's eye: let us then apply the principles of our art to this branch of education. We have no longer need to burthen our memories with long lists of the Latitude and Longitude of places; our symbols will at once direct us where and in what degrees there is the greatest extent of land or water, or what quarter most abounds with islands, lakes, rivers, &c. We shall limit ourselves to General Geography.—The pupil can easily apply these instructions to particular Maps, by taking a symbol to degree, instead of 1 for 10, as is here done:—Procure a Mercator's Chart, but be careful that the degrees of latitude are marked by tens. Cut it longitudinally into halves; if an English Map, at the meridian of London. Again cut it through the Equinoctial Line. You have it now in quarters; by again dividing it at the 90th degrees East and West longitude, you have it in half quarters.
Long. East.
But the most simple method is this:—The globular Map of the World being familiar to all who have the slightest knowledge of Geography:—Divide each Hemisphere into quarters, and either obliterate the figures which mark the longitude (from meridian of Greenwich), or substitute a scale of your own, counting Greenwich 20 East, and onwards to 180 in the Eastern Hemisphere, so that you gain 20 degrees East Longitude, which amount must be subtracted from the former, in order to its agreeing with the common mode of reckoning. According to our plan, for degrees under 20 in the Eastern Hemisphere, deduct their amount from 20, and the remainder is Longitude West; thus, 17 from 20, remains 3 West. And by the same method you lose in counting 20 degrees from the Western Hemisphere, in Longitude West, which amount you will add for a similar reason, until we come to 160 West Longitude; thus—
Or, more particularly, our plan, Longitude West from 160 to 170 degrees, double the Unit of the Degree, and add the difference between that amount and 20; thus, 161, (the 1 being doubled (2), leaves 18; which, added to 161, is 179, Meridian of Greenwich; and this process is exceedingly easy, observing that all under 20 degrees in your Eastern Hemisphere is West Longitude from Greenwich; aud every degree above 180 in the Western is East ​Longitude; thus, a place in 17 degrees East Lon gitude, (by the plan here laid down,) will stand from the Meridian of Greenwich 3 degrees West.
On the front wall, first room, you have one half of the Northern Latitude of the Eastern Hemisphere; opposite to which the half of that of the Western, (making the floor your Equator, as named before.) On the room immediately underneath will be found the Southern Latitudes of each Hemisphere, for which you reckon downwards. You have now one circular window in the front of your house, and another behind, containing the Eastern and Western Hemispheres, divided by the Equator (floor), having in each 180 degrees East and West, beginning with the eleventh symbol, as before directed.
In the squares in which there appears water only, no symbols need be introduced.