IX 



The Chairman said there were some trees 50 or 60 years old at 

 Sandy Bay perfectly healthy and bearing good crops. 



MOUNT BISCHOFF. 



Mr. Stephens referred to a paper read last session, written by Baron 

 Von Groddeck, Germany, entitled, "Remarks on the tin ore deposits 

 at Mount Bisehoff," translated by Mr. G. Thureau, P.G.S. Specimens 

 of the rock described in the paper not having been sent with the 

 paper, Mr. Stephens stated he had received -from Mr. C. P. Sprent 

 specimens of the rock heretofore described as quartz porphyry or eurite, 

 which he had sent to Professor Liversidge, who had kindly given 

 him the following notes :— " I am sorry to say that I have no time just 

 now to make analyses of them nor even sections for the microscope, 

 and without doing both of these it is often very difficult to identify 

 rocks, and not always then. The white rock from Mount Bisehoff, which 

 looks like a quartz pophyry, is undoubtedly a topaz rock as described 

 by Baron V. Groddeck ; the sp. gr. is far too high for a felspathic 

 rock, and it is as rough to the touch as a trachyte, moreover it 

 contains fiourine, which is readily detected before the blowpipe. 

 This association of topaz and tin is a very interesting one. I think 

 topaz crystals oughs to be found in the cavities of the rock. If you 

 can set anyone to collect in the district probably interesting dis- 

 coveries would be made." 



NOTES AND EXHIBITS. 



Mr. C. J. Atkins exhibited specimens mounted for the microscope, 

 a fresh-water alga; (Anacharis alsinastrum), commonly called in Eng- 

 land the water thyme. It is said to have been introduced in England 

 from North America, and has since spread with such rapidity through 

 the canals and rivers as in many instances seriously to impede their 

 navigation. The specimens before the meeting were obtained from the 

 pond in Franklin-square, where it appears to have taken a firm hold. 



VOTES OF THANKS. 



On the motion of Mr. Justin Beowne, seconded by Col. Legge, a 

 vote of thanks was awarded to the various donors and the gentle- 

 men who had furnished papers. 



The meeting then terminated. 



JUNE, 1886. 



The monthly evening meeting of the society was held on Tuesday, 

 June 8th ; Mr. James Barnard (vice president) in the chair. 



The following gentlemen were elected corresponding members :— Mr. 

 Chas. Gould. F.G.S.; Prof. Alexander Agassiz, Curator Museum ot 

 Comparative Zoolosy at Harvard College, Cambridge, Mass.; Prof. 

 Geo. VV. Tryon," jun.; Conservator of Conehological Museum, 

 Philadelphia, 



List of additions to the library during the month of May :— 



Annals and Magazines of Natural History, April. 



Annual report of the Trustees American Museum of Natural History 

 for the year 1885-6.— From the Trustees. 



Athenamm, March. - .„. 



Circulars of information of the Bureau of Education JNo. 1, isst 

 Meeting of the International Congress at Borne in Oct., 1884, JNov/, 

 1884. The teaching, practice, and literature of shorthand by Julius 



