The Geology of the Clltden Basin. 137 



the volume of erosion subsequently accomplished by the river in 

 its ceaseless flow. This post-glacial gorge at Cluden Mills 

 removes the question of date of the Glacial Age from the abstract 

 to the concrete ; but it also supplies us with data by which we 

 may find a satisfactory answer. A careful measurement of the 

 amount of rock removed at the falls in a year, a decade, or a 

 life-time would give us a sure key to one of Nature's locked 

 doors, and reveal her hidden treasures of knowledge within. 



11th March, 1910. 



Chairman — Dr Seiiple, V.P 



X-Ravs Phoiographv. By Dr J. D. Robsox. 



[Dr Robson sketched the histon.- and progress of X-Rays 

 Photography. He then described the mechanical processes 

 necessarv" to its production, and the uses made of it, particularly 

 with regard to surgery. The lecture was illustrated by lime- 

 light \-iews. Dr Robson stated that by permission of the 

 Chairman of Directors of the Infirmary- he was able to in\-ite the 

 members of the Society to a practical demonstration there.] 



Notes ox Outdoor Pl.axt Photographw By Mr S. 

 Arxott, F.R.H.S. 



[Mr Amott dealt with the difficulties attending plant photo- 

 gra^ihy and the methods adopted to secure suitable backgrounds, 

 sufficient sharpness of detail, and the true colour values of 

 flowers. He described the troubles caused by wind, confined 

 space, and awkward position, and exhibited specimens of his 

 work in illustration of these problems and their solutions.] 



