Oct.— dec. 1856,] The Natron Lake of Loondf. 19 



No. 8. Quartz. 



No. 9. Greenish brown glass, very fusible. 



No. 1. This salt appears to be formed in crystalline masses, 

 and is but slightly contaminated by chloride of sodium, or by any 

 other insoluble impurities ; these, exclusive of the water present, 

 will amount to about 4 per cent. 



No. 2. Fine cubical crystals, forming masses, in which the pe- 

 culiar structure may easily be traced ; this salt contains something 

 more than 92 per cent, of common salt, or chloride of sodium. 



No. 3. Has less crystalline structure than No. 1 ; is efflorescent 

 and white in appearance. Chemical constitution shows a larger 

 amount of water, while the soda and carbonic acid are nearly in 

 the proportions required to form neutral carbonate. 



No. 4 is formed by the aggregation of numerous small crys- 

 tals, is whiter than No. 1, but has almost the same chemical con- 

 stitution as No. 3. 



No. 5 appears in larger dirty looking masses, is not homogene- 

 ous in its composition ; in parts, it possesses a beautiful structure, 

 seen in crystals radiating from a centre : contains 16 per cent, of 

 water, 25 per cent, of common salt, and 30 per cent, of insoluble 

 impurities. 



No. 6. A greyish looking earth, containing 58 per cent, of in- 

 soluble impurities, 15 per cent, of water, 2 J of common salt, leav- 

 ing 26 per cent, of carbonate of soda. 



No. 7. A salt varying from all the other specimens, being com- 

 posed of earthy (not alkaline) carbonates chiefly, some insoluble 

 impurities, a little common salt. 



No. 8 not examined, it evidently consists of crystallized silicic 

 acid, known as quartz. 



No. 9. A readily fusible glass, most probably chiefly a silicate 

 of soda, not examined chemically, scratches window glass. 



I have made no remarks respecting commercial value, as this 

 must necessarily depend on various circumstances, concerning 



