How to use clark’s table???

In the required quantity on the table, you are mensioned angle and its value (say tan) next to it

Eg for tan 45^{0} = 1

and for tan 45^{0}15’ search for colunm closest to 15’ it is 12’ then add look in mean diferences table

and find for what u have to add to make it 15

it is 3’

thus the value of tan 45^{0}15’= 1.0000+0.0070+0.0013