DESCRIPTION OF THE LABORATORY AT PLYMOUTH. 101 



of the same material to Laboratories II and III, to the 

 Physiological (Plate II), Laboratory, and to the " Receiving 

 Room (Plate I)." 



The Engine Room. — The engine room (Plate III) contains 

 two patent " Otto " gas engines, one of two horse power (6), 

 and the other of four horse power (a) ; two patent rotary 

 pumps ("Forbes and Edward") in duplicate, each capable 

 of circulating 7500 gallons an hour (d), and two similar 

 pumps capable of circulating 2000 gallons per hour (e). 

 These pumps are of vulcanite, and all the pipes, cocks, 

 taps, &c., concerned with the circulation of the sea water 

 are also of vulcanite. Vulcanite and rubber hose is used 

 to convey the water from the reservoirs to the pumps. The 

 two large pumps supply the tanks in the aquarium, the two 

 smaller pumps the tanks in the Laboratory. In consequence 

 of the necessity to circulate the water continuously, the 

 engines and pumps have been supplied in duplicate. 



For the renewal of water in the reservoirs a Shone's 

 ejector placed at low-water mark has been provided. This 

 ejector is supplied with compressed air from a receiver in 

 connection with a compressor attached to the four-horse 

 power engine in the basement of the building. This 

 engine will thus perform as required the double function of 

 circulating the water through the pipes and tanks of the 

 aquarium and laboratory, or renewing the supply of salt 

 water in the main reservoir from the sea. By this arrange- 

 ment the necessity for a distinct pumping engine and house 

 on the rocks, here exposed to the waves, is avoided. 



The engine room also contains a special receiver for com- 

 pressed air (c), which is distributed to the main laboratory 

 in pipes for the purpose of aerating small aquaria containing 

 minute organisms. 



Receiving Room. — Materials for workers in the labora- 

 tory and to stock the aquarium will be brought by the 

 fishermen into the " Receiving Room" (Plate I). This room 

 is on the ground floor in the western block above the engine 

 room, and communicates directly by means of doors with 

 the yard outside and with the aquarium, and, by means of 

 a lift, with the floors above it. The room is fitted with a 



