148 JOURNAL OF THE [December, 



ROCK INCLUSIONS. 



On this subject, Mr. Hyatt, who exhibited a section of quartz 

 crystal, containing a cavity in which was a moving bubble, said 

 that he did not know what the contents of the cavity were, and 

 he thought considerable uncertainty existed as to the nature and 

 formation of these cavities generally. Heat, he said, was usually 

 thought to be involved in their production ; but, he suggested, 

 might it not be well to ask whether or not cold had any part in 

 their formation ? Would not a particle of frozen water, caught 

 in quartz during the crystallization of the quartz, on subse- 

 quently melting leave a cavity with an air space similar to the 

 specimen shown ? As to the effects of heat on these inclusions, 

 he said that the specimen present had been subjected to a tem- 

 perature equal to that of boiling water without being in any way 

 affected by it. 



Mr. Van Brunt: "A number of rock inclusions, liquids con- 

 taining bubbles, etc. .were shown before the Academy of Sciences 

 and afterwards by oversight left out of doors exposed to severe 

 cold weather. On subsequent examination, several of the speci- 

 mens were found to be split or cracked and their inclusions 

 gone." 



Meeting of November iqth, 1886. 



The President, the Rev. J. L. Zabriskie, in the chair. 



Twenty-four persons present. 



The Code of By-Laws for the government of the Society, re- 

 ported at the meeting of October ist, 1886, was adopted, to go 

 into effect immediately, and to take the place of the Constitu- 

 tion and By-Laws as they existed on the first day of October, 

 1886. 



OBJECTS EXHIBITED. 



1. P yrgodiscus armatus : by E. A. Schultze, 



2. Aiilacodiscus Thiimii : by E. A. Schultze. 



3. Caprella acuminifera ; female with eggs : by F. W. Leg 

 gett. 



4. Fruit of the fungus Microsphceria extensa, C. & P., from 

 leaves of the Pin-Oak {Quercus palustris, Du Roi,) : by J. L. 

 Zabriskie. 



