Cartesian equation:
y = cx2 - log(x)
Click below to see one of the Associated curves.
The case here is where A is on a straight line and was studied by Arthur Bernhart.
Pierre Bouguer was a French scientist who was the first to attempt to measure the density of the Earth using the deflection of a plumb line due to the attraction of a mountain. He made measurements in Peru in 1740. A more successful use of this method by the astronomer Maskelyne placed the density between 4.5 and 5.
The URL of this page is:
http://www-history.mcs.st-andrews.ac.uk/history/Curves/Pursuit.html