On the dimension group of classical physics

The bas ic principles of the group properti es of physical quantities are reviewed. The proble ms assoc iated with th e dimensions of angle and logarithm are solved by using functional equations, ins tead of a nalytic express ions , for de fining functions of non numerical quantities. It is concluded that the neper and radian are related by Np= j rad , so that when the radian is considered as a base unit . the neper becomes a derived unit, and is the 5 I unit for logarithmic quantiti es .