20 



MEMOIR ON EMERY. 



to arrive at what is actually contained in the mineral. The 

 filtered solution is heated with a little nitric acid to convert all 

 the protoxide of iron into peroxide ; then treated with an 

 excess of caustic soda and a little carbonate of the same alkali; 

 this redissolves the alumina first precipitated, and thus sepa- 

 rates it from the oxide of iron and a trace of lime. The iron 

 and lime are separated in the ordinary way ; the alkaline solu- 

 tion of alumina was acidulated, and the alumina precipitated 

 with carbonate of ammonia. 



Thus analyzed, the emery from different places gave the 

 following results : 



No. 



10 



Localities. 



Kulah.... 

 Samos.... 

 Nicaria . 

 Kulah ... 

 Gumuch 

 Naxos..., 

 Nicaria . 

 Naxos.... 

 Gumuch 

 Kulah.... 





57 

 56 

 56 

 53 

 47 

 46 

 46 

 44 

 42 

 40 





4.28 

 3.98 

 3.75 

 4.02 

 3.82 

 3.75 

 3.74 

 3.87 

 4.31 



Chemical Composition". 



1.90 

 2.10 

 2.53 

 2.36 

 3.11 

 4.72 

 3.10 

 5.47 

 5.62 

 2.00 



63.50 

 70.10 

 71.06 

 63.00 

 77.82 

 68.53 

 75.12 

 69.46 

 60.10 

 61.05 



33.25 

 22.21 

 20.32 

 30.12 

 8.62 

 21.10 

 13.06 

 19.08 

 33.20 

 27.15 



92 1.61 

 62 4.00 

 404.12 

 50J2.36 

 80J8.13 

 .10 



6.88 

 2.41 

 1.80 

 9.63 



101.18 

 99.03 

 99.43 

 98.34 

 99.48 



101.31 

 98.88 

 99.23 



101.20 



101.13 



I ought to mention that the analysis afforded other sub- 

 stances in small quanties in some of the emeries, as titanic 

 acid, oxide of manganese, oxide of zirconium, and sulphur (ex- 

 isting 'in pyrites); but these substances are unimportant in the 

 composition of emery, and are in such minute quantities that 

 it is necessary to operate on a considerable quantity of the 

 mineral to obtain satisfactory results concerning them. 



The analyses marked 6 and 8 were made by decomposing 

 the emery as it came from the sieve, without pulverization in 

 the agate mortar. It was by accident that it occurred, and I 

 was not aware of the neglect until it was fused with the bisul- 

 phate of soda; but, not wishing to lose the analysis, the opera- 

 tions were continued as in the other cases, only using a little 

 more of the bisulphate in the second decomposition; and some- 

 what to my surprise the decomposition was quite as perfect as 

 in the other cases. I had nearly completed all my analyses 



