William Joshua and fresh water algae

In 1894, the Banffshire Journal published a long article about William, mainly on research he had carried out on rotting turnips and a possible link to an insect. The article also painted a wider picture of William’s researches including:

“Mr Sim has also done good work in botany; and some time ago he discovered three species of fresh water Algae new to Britain.”

In 1882, William Joshua, a naturalist from Cirencester, published an article about British freshwater algae. He also advertised in Hardwicke’s Science Gossip, a journal which the Sims read and to which they contributed short articles. He was seeking other naturalists to correspond with him and exchange specimens of algae. One year later, in 1883, Joshua published a second article about freshwater algae and twelve of those he listed had come from Den of Gight. This was a location close to their farm at Gourdas with which the Sims would have been familiar – but which was unlikely to have been known to Joshua unless he had help. Did William find the new algae and send them to Joshua who published the find?

Further research led to collections of William Joshua’s microscope slides in the Natural History Museum, London, and University of Limerick, Republic of Ireland. Some of these slides identified the source of the algae as Den of Gight, Aberdeenshire, including one marked as a new British species.

NMH slide 2NMH slide 1

Slides from Natural History Museum

All of the research seems to support the statement made about William in the Banffshire Journal. I have found some references to William Joshua but nothing, such as letters, that provide a definite link between him and William Sim. Is there anything more out there to help this research?