432 Proceeding. 



magnesia, as one ten-thousandth of a grain of magnesium can be recognized in one-half 

 a grain of liquid. Baryta and alumina do not absorb iodine in the same way as magnesia. 



3. " Ou Alotropic forms of certain Zinc and Cobalt Salt," by "W. Skey. 

 (Transactions, p. 387.) 



This paper recorded further additions to the list of dimorphic substances. 



4. "On the Eelation between Pitch Stones and Quartz Porphyries of 

 the Mount Sumner's District, Canterbury," by S. H. Cox, F.G.S. 



ABSTBACT. 



This paper gave the results of the microscopic examination of a large series of these 

 rocks, and was beautifully illustrated by means of thin slices of the rocks being 

 thrown on the screen by the oxyhydrogen microscope. The argument of the paper was to 

 show that the primary form of the rock is that of Pitch-stone, and that a gradual 

 passage can be traced from the vitreous Pitch-stones with laminated structure to the 

 massive and crystalline Quartz-phorphyries, by a process of devitrifiation, and further, 

 that it is therefore not necessary to assign these rocks to different periods of eruption. 



Dr. Hector stated that this was the first of a series of investigations that would be 

 extended to all the other igneous rocks of the colony, the result of which, when fully 

 published with illustrations, would be of great importance, not only in assisting in 

 geological classification, but also in throwing light on the circumstances under which 

 valuable minerals and metalliferous lodes occur. In giving a general description of the 

 probable causes which have led to the formation of the volcanic rocks, he exhibited 

 Prof. Marcou's recent geological chart of the world, as showing that we are acquainted 

 with the structure of only a very smaU portion of the land surface, whUe of the two-thirds 

 of the globe covered by sea we are necessarily ignorant, unless we except recent inferences 

 made as the result of the "Challenger" expedition, which are considered to prove that 

 the great ocean-beds are probably of higher antiquity than most of the geological for- 

 mations. 



At the close of the meeting the chemical tests referred to in Mr. Skey's paper were 

 shown, and the sections of rock alluded to by Mr. Cox were demonstrated by polarising 

 microscopes. Dr. Hector also exhibited a series of lantern views of the scenery of Te 

 Anau Lake and Stewart Island, which he had recently obtained. 



Annual Meeting. 12th February, 1881. 

 Mr. Mabtin Chapman, President, in the Chair. 

 Neiv Members — H. Hill, Napier, E. S. Hawkins, Masterton. 



abstract of annual report. 



There have been seven general meetings of the Society held during the past year. 



The papers read are as follows : 7 on Geology ; 7 on Zoology ; 8 on Botany ; 3 on 

 Chemistry, and 5 on Miscellaneous subjects, making a total of thirty communications. 



Thirteen additional members have been added to the roll, five have either withdrawn 

 or been transferred to other Societies owing to removal, and two have been lost to the 

 Society by death. The total number now on the books being 287, namely 6 in addition 

 to last year's list. 



One hundred and one volumes have been added to the Library during the past year, 



