Original sentence: (Maxwell's 1865 formulation was in terms of 20 equations in 20 variables, he later attempted a quaternion formulation).The change to the vector notation produced a symmetric mathematical representation that reinforced the perception of physical symmetries between the various fields
Edited sentence: (Maxwell's 1865 formulation was in terms of 20 equations in 20 variables, although he later attempted a quaternion formulation that proved awkward.) The change to the vector notation produced a symmetric mathematical representation that reinforced the perception of physical symmetries between the various fields