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?
As for the first, 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.