First, I'll note this interesting thread: #4158384. However I unfortunately don't have privileges to post there so I'll start this new one. I'm trying to make my own sliderule. How did they do it? How did Napier invent his "bones?" A more particular question would be: If I make a table of powers of 2, arraying them along a numberline, and a similar table of powers of 3 (9,27,81, etc) then, could I combine these? I know the answer is "yes" since that's what a sliderule DOES, but I don't know how to reconcile the two. Where, on the table of x2 logarithms, do I etch in the 3?