When finding error in magnetic compasses, just remember that True
Virgins Make Dull Company at Weddings, and that Dead Men Can't Vote Twice at Elections. Alright,
so these are just memory devices, but you won't forget them, will you?
The first letter
of each word in the phrase True Virgins Make Dull
Company at Weddings is representative of a different part of the formula used to find
compass error. The diagram at right explains.
The second phrase is exactly the same as the first, but in
reverse, and as such, rather than adding West error, you are now adding East error.