1832.] On the Gypsum of the Himalaya. 293 



even those parts so fragmentary, and so interspersed with the 

 coarser varieties, that any attempt at converting it into ornamen- 

 tal uses would, I fear, be out of the question. The specimens that I 

 have seen in cups and small vases fully authorize this conclusion : 

 their appearance heing more of a white earth, or chalky limestone, 

 than of a gypsum, or to speak in plain terms, of an alabaster. The 

 varieties of Himalayan gypsum as yet discovered are certainly deficient 

 both in beauty and value as an article of use, though interesting 

 for comparison with other formations. 



Selenite, in small tabular crystals, is disseminated throughout this 

 gypsum, though in hardly sufficient abundance to give any peculiar 

 character to the formation. 



A question of considerable interest arises from the appearance and 

 position of the above-mentioned deposits, which, as mentioned in a 

 former part of this paper, from their position under rocks of the prima- 

 ry and secondary classes, acquire an appearance of antiquity, not 

 borne out by the general history of the mineral ; namely, that the 

 gypsum throughout the globe is simply an infiltration analogous 

 to the tufa and calcareous deposits, and depending on causes 

 chemically similar ; the sulphuric acid being the active generator 

 instead of the carbonic. If in the proximity of sulphur an excess 

 of oxygen would produce sulphuric acid, a difficulty is remov- 

 ed, and the contact with lime-rock or carbonate of lime would, 

 it may be supposed, produce its sulphate, or gypsum ; and I cannot 

 perceive the improbability of such a process having been or being still 

 in force ; or that nature's laboratory might not have been as active 

 in the dissemination of gypsum, as it is in the present day, of the 

 calcareous tufa. 



The argument obtains considerable weight from a most material 

 circumstance, which almost makes it a matter of certainty that the origin 

 of all gypsums is contemporaneous ; this is, the exact resemblance 

 both in texture and crystallisation that they all bear, whether Alpine, 

 or those varieties found with the secondary rocks : a similarity that 

 does not exist in any of the lime-stones formed at different periods, nor 

 in other rocks : the primary and secondary varieties shewing the 

 most decided dissimilitude both in texture, quality, and position. 



The term infiltration must be received, as implying the simple power 

 of a mineral in solution to insinuate itself into cracks and fissures, or to 

 fill hollows and cavities, without any reference to a gradual process, as 

 it is possible that the mineral m question might in many instances (parti* 



