OP ARTS AND SCIENCES. 181 



nation of this matter, that 10 cm.^ of the anhydrous ether-alcohol mix- 

 ture extracted from 0.5 grm. of sodium chloride 0.0005 grm., and 

 from 0.5 grm. of potassium chloride 0.0003 grm. Smith's mode of 

 applying the method is better than the original ; for, by taking care 

 not to heat the mixed salts above 100° C, the danger of decomposing 

 the lithium chloride is diminished, and by treating the dried salts 

 with the ether-alcohol mixture in the capsule in which it is heated and 

 weighed (protecting it by a small inverted bell-glass) the disadvantage 

 of the transfer is avoided, but the danger is incurred that the mixed 

 salts may not be thoroughly dried by heat so gentle. With this 

 modification Smith obtained results which are rearranged in the fol- 

 lowing statement, and which do not throw a very favorable light upon 

 the method.* 



It is obvious, therefore, that neither the method of Rammelsberg 

 nor that of Mayer may justly claim to be what a good process should 

 be, accurate and rapid ; and in the dilemma many chemists have been 

 inclined to accept, with Bunsen,t the inherent disadvantage of an in- 

 direct process, and in a mixture of sodium and lithium chlorides cal- 

 culate the percentage of each from the known weight of the mixture 

 and its contents in chlorine, and in a mixture of the three chlorides 

 calculate the percentage of each from the known weight of the mix- 

 ture and the determined contents in chlorine and potassium. Here 

 again, however, as in Rammelsberg's process, the difficulty of bringing 

 the chlorides to a definite condition for weighing without decomposing 



* Dr. Smith's language in the description of these experiments is somewhat 

 ambiguous, but it is believed that these figures represent the meaning intended. 

 After the presentation of the data of the first experiment given here with the 

 correction of an obvious typograpliical error, it is said of tiie second and third 

 experiments that " a similar mixture containing 18.10 per cent of chloride of 

 lithium furnished a residue of 17.65 per cent," and " a similar mixture contain- 

 ing 67.20 per cent of chloride of lithium gave a residue of 68.40." I have taken 

 this to mean that in all three experiments 0.2 grm. of sodium chloride and 0.2 

 grm. of potassium chloride were employed with the different proportions of 

 lithium chloride indicated for each experiment. At all events, if this is not the 

 meaning of the language made use of, it is difficult to see a definite value in 

 the experiments. 



t Ann. d. Chem. u. Pharm., cxxii. 348. 



