Production began to taper off in the 1870s (except for an anomalously large coinage in 1881), but mintage of the denomination did not finally end until 1889.
As the summer monsoon season comes to an end and afternoon showers begin to taper off, the river settles down and clears nicely, allowing the fun to begin.
In most natural occurring materials, the magnetically coupled response starts to taper off at frequencies in the gigahertz range, which also means significant magnetism does not occur at optical frequencies.