132 TURQUOIS STONE. 



this instrument, will make sufficiently evident; the barometer 

 alone, therelore, is not sufficient; but in assisting the judgment 

 of the seamen, is capable of rendering very important services to 

 navigation. 



VI. 



Analysis of the Substance hiotvn hy the name oj Turquois. By 

 M. Bouillon Lagkange. 



.ANY Mineralogists have placed fhe turquois among 

 calcareous bodies and the genus called opake ; and others, on 

 account of their blue or green colour, have classed them among 

 the ores of copper. 

 Chaptal'sac- " The turqaoises, (says M. Chaptal) are merely bones co- 



TuiQuois s'pne 'oured by the oxsdes of copper. The colour of the turquois 

 often passes to green, which depends on the state of the me- 

 tallic oxide ; the turquois of Lower Languedoc emits a fetid 

 smell by the action of fire, and is decomposed by acids ; the 

 turquois of Persia emits no odour, and is not attacked by acids. 

 Sage suspects that the osseous pajt is azatized in those left." 

 Places where Many turquoises are found in Persia, but none in Turkey, 

 icy are tound ^^ jj.^ j^gj^^g seems to imply. They are obtained from two 

 mines : the one, called the Old Rock*, at three days journey to 

 the north-west of Meched, near Nichaburgh; the other, at 

 five days 'ourney, is called the New Rock. The Turquoises 

 of this last place, are of a bad blue, inclining to white, and are 

 therefore cheap. But since the close (if the last century, the 

 King of Persia ha- prohibited the Old Rock to be explored, 

 except f(ir himself; because the woikmen of the country work- 

 ing on'y irr wire {en fit), and not being acquainted with the 

 art ofenamell ng on gold, they made use of it (or the mounting 

 of sabres, poignaids and olher tools, turquoises of this mine, 

 in teaJ oi enamel, by cutting and setting (hen in different 

 forms, 



I shall add some other details, extracted from different 



works J 

 * Annates (le Chymie, LIX, 180. 



La Harpe's Abrege des Voyages, VI, 507. • 



