Write the sentence "Blithely light, lightly light, take one tasty bite" with no spaces, capital letters, or punctuation. Then mark the number 1 above the b in "blithely", and the numbers 1.5, 2, 3, 4, 5, 6, 8, and 10 under the last letters of every word. The distance between these numbers is proportional to the logarithm of their values. You can use your logarithmic scale as a Gunther's rule: with your fingers, add the value 2 segment's length to the value 4 segment and see how long a segment results. Make two scales of identical proportions and use them as the C and D scales on your own personal slide rule. I found the "mosquito rule" in a book of nomography for chemical engineering.