Question about weird number table on compass lid

My dad has a standard Warren-Knight compass with a fold-down lid. When you lift the lid up, there is a 6x6 number table at the bottom, with a line emanating from the top of it to the other side of the lid. The number table is the numbers 1-36, with each odd row backwards, so row one is 6, 5, 4, 3, 2, 1, and row 2 is 7, 8, 9, etc., row three is 18, 17, 16, etc. Think of starting in the upper right, and snaking across to the bottom right. Can anyone tell me what the heck this table is for or what it means? Thanks.

Just guessing that it’s a “fixed declination scale” for figuring compass magnetic variations, but I don’t understand how it works, sorry.

Sounds like sections in a Township to me, though why they would be on a compass lid is beyond me.

A township is made up of 36 sections aligned as you describe.