Maximilian Toch (1864-1946) was an important American industrial chemist and amateur photographer active in the 1890’s and into the early 20th century. His interest in photographic chemistry and films were the subject of his writings in journals such as  The Photographic Times-Bulletin around this time.  Commentary on this photogravure by Toch showing the clock tower Big Ben and Westminster Bridge in the pages of the November issue:

Our photogravure frontispieces have always been a feature of this publication, and we have always endeavored to have them made from subjects of artistic merit. Our frontispiece this month is one of unusual interest and excellence. The original negative was a snapshot made by Mr. Maximilian Toch, on Ansco film, the exposure being made during a heavy shower. Aside from the charming atmospheric effect and general excellence, the print is a very strong endorsement of the claims make for the great latitude in exposure of the Ansco film. We only regret that the reproduction, excellent as it is, fails to show all the beauties of the original.  (1.)

Toch had been a delegate to the International Congress of Applied Chemistry in Berlin, Germany in June of 1903, and published a brief account- The Photo Chemical Session of the Congress of Applied Chemistry at Berlin– in the September issue of The Photographic Times-Bulletin.  It is most likely this rainy day London view was taken while he was on this European trip. An excerpt of his article on the Berlin Congress:

THE International Congress of Applied Chemistry was held in Berlin at the Reichstag from June 1-10, 1903, delegates from various chemical societies from nearly all countries being present. The proceedings held at the Photo Chemical section were perhaps the most interesting. The delegates from the Society of Chemical Industry and the American Chemical Society being Dr. Leo Baekeland, Maximilian Toch and William McMurtrie. A number of prominent German chemists and scientists were present, among whom were Drs. Miethe, Eder, Von Knorr and Prof. Liebrich.  (2.)

1. Trade Notes: in: The Photographic Times-Bulletin: November, 1903: pp. 525-526
2. Ibid: September: pp. 419