Proceedings. xlvii 



F/ujhth Eveiiinfi Meeting, Decnnher 8th, 1886. — The eighth 

 Evening Meeting was held on December 8th. The first paper of 

 the evening was by Dr. George J. Hinde, " On the Microscopic 

 Structure of the ' Mahii,' or Firestone Eock of Merstham and 

 Godstoue" (Teans., art. G3). The discovery of the composition of 

 this rock is due to Dr. Hinde's researches, and is of great geo- 

 logical interest. He finds that the stone is almost entirely made 

 up of the spicules of fossil sponges. In his paper, which I need not 

 refer to in much detail, as it will doubtless appear in our Trans- 

 actions, ho described the geological position of the rock, the 

 geograjihical limits of its outcrop, and illustrated its composition 

 by an admirable series of diagrams and of microscopic preparations. 



An interesting discussion followed, in which the remarks of 

 Mr. Topley, Mr. Stanley, and others were of much interest. 



Mr. Topley then gave an account of the new well at Addiugton, 

 which is being sunk by the Corporation, in which, after some 

 disappointing delays, a copious supply of water amounting to 

 about 1,200,000 gallons per day has recently been obtained. Mr, 

 Topley gave interesting particulars of the nature of the chalk- 

 fissures in which the water flows, and of the position and dip of 

 the strata, illustrating his remarks by maps and diagrams. 



The meeting had the advantage of the presence of Mr. Thomas 

 Walker, the Engineer to the Corporation, under whose direction 

 the works are being executed; of Mr. Morland, the Chairman of 

 the Water Committee; and of Mr. Baldwin Latham, whose un- 

 equalled knowledge of the water-bearing strata of the district is 

 so well known. The discussion therefore brought out a large 

 amount of valuable information, and was extremely animated. 



Mr. Topley spoke favourably of the prospects of obtaining 

 water from the underlying Greensand, if the well should be sunk 

 down to it. He pointed out that the water-supply from that 

 formation would probably be much softer than that from the 

 Chalk, thus rendering unnecessary the artificial softening of 

 the Croydon water, which has recently been strongly advocated 

 by some members of the Corpoi'atiou. 



The meeting was one of unusual interest, the practical 

 importance of the subjects under discussion being appreciated 

 by all present. 



Cunverscttioiiul Meetings. — Conversational Meetings have been 

 held during the year ; those devoted to photographic topics have 

 been very successful and well attended. At that held on October 

 27th Mr. Low Sarjeant demonstrated the Collodio-Bromide- 

 Emulsion process through all its stages, from the coating of the 

 plate to its development and finish as a lantern -slide. On 

 November 24th Mr. James Epps, jun., kindly brought his lantern, 

 and fifty photographic slides (all the work of our own members) 



