1867.] 143 [Fleury. 



perties of silica or quartz ; we have seen it in a solid, semi-solid or 

 gelatinous, and in a Wjuhl state, much like carbonic acid, which can 

 be frozen to solid crystalline ice, or to a light flaky mass like snow, 

 or be kept as a refreshing baverage entirely dissolved in water. 

 We will now return to the spot from whence we have taken our speci- 

 men and attempt to unravel its history. 



It is part of a vein, some five feet wide, traversing a solid rock 

 called argillaceous schist. How did the quartz come into this rock ? 

 Was it melted by heat and like glass, or scoria, pressed up thi'ough 

 the crevice of the rock, or has it, as an aqueous solution, been in- 

 filtrated from below and gradually hardened ? 



Oil' forefathers were great friends of the igneous theory ; they con- 

 cluded that because they had known and learned of volcanic action 

 lifting up hills and mountains, and were familiar with the tact that 

 certain stones when exposed to great heat can be fused like glass, all 

 rocks, such as granite, gneiss, quartz, etc., were the results of igneous 

 action. It took many y«!ars to dissipate this preconceived erroneous 

 idea, in order to give room to a more reasonable exposition of the or- 

 igin of rocks. 



Flint stones of a rounded form were found to contain cavities filled 

 with water ; they were called geodes. How could this water come 

 into the stone, had it been melted by fire? Even some quartz crys- 

 tals, perfectly formed, were found to inclose cavities filled with a 

 liquid. Finely cut laminjB of granite were subjected to microscopic 

 observation and disclosed pores filled with water. It was further 

 observed that quartz veins traversed rocks which were evidently of 

 sedimentary character, — and as they showed no evidence of ever having 

 come in contact with a highly heated liquid mass, where they touch 

 the quartz vein, it was finally concluded that these quartz veins must 

 have been formed by aqueous and not by igneous action. 



The question now arises: From whence did the quartz come, and 

 how is it that the sulphurets are inclosed and firmly embedded in its 

 centre ? 



As none of us were present when this quartz rock was formed, we 

 can only draw our inferences by comparative induction, and thus 

 gradually reach the true cause. 



We will again inquire of the science of chemistry, and ask her if 

 she cannot lend us her assistance to uni-avel this knotty question. 



Professor Fremy of Paris, one of our best practical chemists, has 

 examined the chemical properties of silicium and its combinations 

 with chlorine, fluorine, sulphur, iodine, bromine, carbon, and has re- 

 cently published his results in the Traite de Chimie. 



The most important subject for us here, and the one very little 

 known, is his description of the combination of silicium with sulphur, 



