THE ESSEX FIELD CLUB. 155 



He remembered that when the sewers were being dug at Chingford and 

 Walthamstow some years back, many fine crystals were obtained by the work- 

 men. They used to call them " frozen " or " congealed " water. 



Mr. Scourfield, Mr. Elliott, and Dr. Audeu confirmed these statements. 



Mr. F. H. Varley, F.R.A.S., having, as a member of the Council, taken 

 the chair. 



Prof. Meldola delivered a most interesting lecture upon "Mimetic 

 Insects." The subjects treated were, the production of colour in the living 

 organism— Adaptation in colour and pattern to the environment — Protective 

 and aggressive resemblance — Wallace's theory of "warning colours" — The 

 parallelism between protective resemblance and mimetic resemblance —The 

 Batesian theory of mimicry and its limitations— Extension of the theory by 

 Fritz Miiller— Later researches on the subject of "Common warning colours." 



The lecture was beautifully illustrated by natural-colour photographs 

 taken by the Sanger-Shepherd process, the specimens being chiefly from the 

 collections in the Hope Museum, and arranged for the present lecture by 

 Professor E. B. Poulton, F.R.S., Hope Professor of Invertebrate Zoology, 

 University of Oxford. These unique photographs were shown by means of 

 the electric lantern. 



The lecture was listened to with marked attention by the large audience, 

 and was frequently applauded. 



The Chairman in moving a cordial vote of thanks to the lecturer, con- 

 gratulated him on having delivered an admirable exposition of one of the 

 most striking theories of modern biology, and also on his re-appearance in 

 the Presidential Chair after an interval of i8 years. Mr. Varley also alluded 

 to the excellent examples of the new art of producing natural-colour photo- 

 graphs which had been made by Mr. Sanger-Shepherd, v/hich proved the 

 value of the process as a means of illustrating lectures such as that to which 

 they had all listened with so much profit and pleasure. 



The vote of thanks was seconded by Mr. T. Spiller, F.C.S., and carried 

 amid applause. 



Prof. Meldola, in responding, expressed his indebtedness to Prof. Poulton 

 for the beautiful examples selected from the Hope Museum. That Museum 

 under Prof. Poulton's enthusiastic curatorship, had gradually acquired what 

 was probably the finest collection illustrating " mimicry " and " protective 

 resemblance " in Europe. He was also much obliged to Mr. Sanger-Shepherd 

 for the care and skill shown in making the lantern slides. 



THE 207TH ORDINARY MEETING. 



Saturd.^v, December 14TH, 1901. 



The 207th Ordinary Meeting was held in the Physical Lecture Theatre 

 of the West Ham Technical Institute, at 6 30 p.m., the President, Prof. R 

 Meldola, F.R.S., in the chair. 



Mr. Frank P. Smith was elected a member of the Club. 



