Recall that you must choose a set of independent coordinates PRIOR to using Lagrange’s equations. One way to verify that your choice of generalized coordinates are independent is to: hold all but one ...

MR. A. B. BASSET, in a letter to NATURE of August 2, states that the theory of the mixed transformation was first given by himself in 1887, and refers to his treatise on “Hydrodynamics,” vol. i. p.