Extraction of Salts from Sea-Water. 97 



This is very nearly the composition of calcined human bones." 

 Similar characters are found in fossil and recent Orbicula, and 

 also in Conularia, a shell probably belonging to the Pterojooda, 

 a very different group of mollusks. On the other hand, species 

 of Atrypa, Leptcena, and other genera belonging, like Lirigula, 

 to the JBrachiojwda, were found to have the composition of ordi- 

 nary shells. This selection of phosphate of lime by some of the 

 lower animals, no doubt poinfs to peculiarities in their food and 

 habits, to which both zoologists and geologists would do well to 

 direct their attention. 



The present Report contains a collected and condensed state- 

 ment of the valuable remarks of Mr. Hunt on the composition 

 and origin of metamorphic rocks. To attempt any summary 

 of them would be unjust to their author ; but we earnestly com- 

 mend them to the careful study of all geologists who desire to 

 understand the chemical principles involved in the conversion 

 of sediments deposited in water into crystalline and metamor- 

 phic masses, — a very important subject, hitherto too much ne- 

 glected. 



Mr. Hunt's Report also contains several essays on highly 

 important practical points. Two of these, on the manufacture of 

 Iron and on the extraction of Salts from sea- water, have been trans- 

 ferred to this Journal ; and there are others equally valuable, 

 on Magnesian Mortars and the manufacture of Magnesia from 

 Canadian rocks, on the preparation of Plumbago, and on Peat 

 and the products from it. 



This Report, from its more compact and readable form, will be 

 more extensively read and consulted than any of the previous 

 Reports of Progress ; and with the accompanying maps, it will 

 still further establish and extend the reputation of the "Canadian 

 Survey for accurate and able work. 



J. W. D. 



ART, XI. — On the Extraction of Salts from Sea- Water .* 



The manufacture of salt froni the ocean has, from an early 

 period, been a most important branch of industry for the south 

 of Europe. Without reverting to high antiquity, we may cite the 

 salines of Venice, to which that republic owed the commencement 



* Prom the Reports of the Geological Survey of Canada for 1853-5.6, 

 pp. 404-419. 



B 



