196 SEIDELL! BROMINE METHOD FOR PHENOLS 



wires the capacity not only depends upon the relative positions 

 of the two wires, but upon their potential with respect to the 

 earth. The capacity as usually computed requires that the poten- 

 tial of one wire shall be as much above earth potential as the 

 other is below earth potential. To make sure that this require- 

 ment is fulfilled in practice, a special net work is arranged in which 

 there are two indicating instruments, both of which must show 

 zero current. Altho somewhat complicated, this method gives 

 satisfactory results in those cases where the capacity to earth is 

 an important factor. 



The methods here outlined have been found to give satisfactory 

 results with resistances from 1 to 10,000 ohms. With coils the 

 resistance of which lies between 1 and 1000 ohms it was possible 

 to measure the inductance with such accuracy that the error in 

 the time constant (L/R) deduced from this measurement is not 

 more than 10~ 9 second. For coils with a resistance of more than 

 1000 ohms the corresponding limit is 10~ 8 second. 



ORGANIC CHEMISTRY.— A new bromine method for the deter- 

 mination of aromatic phenols. Its special application to 

 thymol. Atherton Seidell, Hygienic Laboratory. Com- 

 municated by Walter Wyman. 



A quantitative method for the determination of thymol being 

 desired for use in experiments upon the solubility of this compound 

 in various solvents, a search of the literature was made for a suit- 

 able method. Those found were the Messinger and Vortmann 

 iodine method (Ber. 23: 2753. 1890), the various adaptations 

 of the bromine method with Koppeschaar's bromate-bromide 

 solution, and the diazonitraniline method of Riegler (Buletinal 

 soc. sciinte. Bucuresci, 8: 51. 1899). Experiments with the 

 first two of these gave unsatisfactory results and the sources of 

 the errors were carefully investigated. In the case of the iodine 

 method an absolutely definite ratio of thymol to alkali was found 

 to be required in order that accurate results might be obtained, 

 therefore necessitating the knowledge of the amount of thymol 

 before beginning the determination. The difficulties which were 

 encountered with the various adaptations of the bromine method 

 appeared to be due to the too energetic action of the bromine in 



