Manuscript trace of self-recording tide gauges in Algoa Bay and Port Alfred, Cape Colony showing the waves caused by the earthquake at Krakatoa, Straits of Sunda, August 1883.
There is an ms letter enclosed, to the RSE from William Shield who was "carrying out some harbour works at Algoa Bay at the time of the occurrence". The writer describes the effects of the waves; in brown paper roll with label entitled "Plans of Port Elizabeth Harbour Works" incorrectly  
This is ink on tracing linen.