Diagram, experimental equipment by Thomas Carnelley and Thomas Wilson A diagram of a conical flask fitted with a two-holed rubber stopper. A glass tube is inserted into each hole. The diagram is accompanied by a corresponding photograph of the equipment and an engraved print. Subject: Microbiology / Bacteriology / Scientific apparatus and instruments The print was published in volume 44 of the Proceedings of the Royal Society alongside the paper 'A new method of determining the number of micro-organisms in air'. 1888