938 Transactions of the American Institute. 



FLUroS IN CRYSTALS. 



At a late meeting of the Manchester Literary and Philosophical 

 Society, Mr. J. B. Dancer gave a history of the discovery of fluids 

 in crystals, including Sir Humphrey Davy's chemical experiments 

 with fluids and gases obtained from the cavities in quartz crystals: 

 Sir David Brewster's discovery of the pressure in the diamond, 

 ruby, emerald, amethyst, cbrysoberyl, &c., of the existence of 

 minute crystals in such cavities, and of the two remarkable fluids, 

 colorless hydrocarbons, found in amethyst from Siberia and quartz 

 from Quebec, named brewsterline and cryptoline; both are some- 

 times found in the same crystal, but are not miscible. Brewster- 

 line is said to be thirty-two times more expansible than water. Mr. 

 Dancer described numerous crystals from various parts of the globe 

 examined by him, which contained fluids; the most noticeable being 

 in fluorspar of Derbyshire, which burst at ISC'* F. temperature. 

 He suggested the employment of the microscope in distinguishing 

 spurious from real transpai*ent gems. At the conclusion of his 

 remarks, crystals containing fluids were exhibited under the micro- 

 scope, and while under examination the temperature of each was 

 elevated to show the expansion of the fluid within it. 



THE DRAGON TREE. 



The giant specimen of the dracoena draco, growing at Orotova, 

 in the island of TeneriflTe, was destroyed in autumn last in a gale 

 of wind. This tree was first brought into general notice by Hum- 

 boldt, about sixty years ago, when he computed it to be six thousand 

 years old. 



EFFECT OF FROST ON LARV^. 



A paper addressed to the French Academy of Sciences by M. 

 Reiset, contained a statement that the general belief held by 

 farmers, viz: that a severe frost kills noxious insects and larvae 

 which grub in the earth, is a fallacy. Emile Blanchard, after com- 

 plimenting Reiset for his researches, said the fact was well kno^vn 

 to naturalists that larvce feeding on roots remained near the surface 

 of the soil during mild weather, and descended to greater depths 

 as the cold became more intense, so as to always escape the efl!ect 

 of frost. Mr. Chevreul said that Reiset had done good service iu 

 ascertaining, by precise experiments, at what depths, according to 

 temperature, larvse would be found in the soil. While the ther- 

 mometer stood at fifteen degrees C. below the freezing point, and 

 the ground was covered with snow, the soil ut a depth of fifty centi- 



