1813.] 



Linncem Society, 



38S 



It is by no means unlikely that the proportion of water here 

 assigned is too small j for nobody can believe that all the water 

 present can be driven oif at a heat below redness. Theory gives 

 us the constituents of arragonite as follows » 



Lime 55*50 



Carbonic acid 42*23 



Water . . 2*27 



100 



Now it is certainly a very odd circumstance that so small a por- 

 tion of water shoiiid act in this case as the cement. The weight 

 of an atom of anhydrous carbonate of lime is 47*9, and that 

 of an atom of water 8-5. Flence it would appear that every 

 atom of water in the arragonite is surrounded by eight atoms of 

 carbonate. This might be conceived to form a cube ; but never 

 could constitute the tetrahedron which Haiiy conceives to be the 

 form of the integrant molecule of arragonite. Mr. Hulme 

 proposes to call arragonite hydrous carho7i(Ue of lime. 



On the 20th of April a fossil chama cor, filled with primitive 

 crystals of carbonate of lime, supposed to be from Wiltshire^ 

 was exhibited by Mr. Sowerby. 



A fossil turtle, from a quarry in Dorsetshire^ was exhibited by 

 Mr. Bullock. The specimen was very perfect, and exhibited the 

 shell of the turtle almost complete. The quarry, from the 

 pieces of stone attached to the specimen, I conceive to be lime- 

 stone. Only another specimen of fossil turtle was found in thig 

 quarry, and it was broken in taking it out. 



A letter from Mr, Heyne was read^ giving an account of a 

 very singular change which takes place daily in the leaves of a 

 species of cotyledon from India, which is cultivated in our 

 hot-houses. In the morning these leaves are as sour as the leaves 

 of sorrel, at noon they are tasteless, and in the evening they 

 are somewhat bitter. Mr. Heyne explains this singular change 

 by supposing that the plant absorbs oxygen ^as during the night, 

 and forms an acid which is again decomposed during the day. 

 Though this explanation be very unlikely to be the true one, the 

 phenomenon certainly deserves to be particularly examined^ 

 What is the acid ? and what becomes of it ? 



A paper by Mr. Anderson was read, giving a description of a 

 new species of rubus, which he observed first in Wales, and 

 afterwards in Perthshire and Aberdeenshire. It is the same 

 which was observed by Mr. Hall at Loch Ness, and which he 

 described in the Trarisactions of the Royal Society of Edinburgh. 

 It is found likewise in Yorkshire^ and many other parts of Great 

 Eritain. • 



Vol. L W V\ 2 B 



