3.02 g (48.0%) of 1,2,4-tribromobenzene, mp 44-44.5°( sample E). Both products were then recrystallized from 95 % ethanol.Degradation of Sample E. The methods used were as for degradation of sample A. From 1.0 g of sample E, 0.57 g (76%) of p-dibromobenzene, mp 86-87°after two recrystallizations, was obtained. This is sample F. From 1.0 g of sample E, 0.74 g (83%) of 3,4-dibromobenzoic acid, mp 233-234.5°, twice recrystallized from aqueous ethanol, was obtained; this is sample G. Isomerization of la in the Presence of 2b. By the procedure described above, a solution of potassium anilide in ammonia (450 ml) was prepared from 0.391 g of potassium metal and 1.86 g of aniline, a solution of 3.15 g of inactive la and 1.05 g of sample D in 50 ml of ether was added to it, reaction was allowed to occur for 15 min, and the two tribromobenzenes were separated by chromatography on alumina. Obtained were 0.88 g of 1,3,5-tribromobenzene, mp 119.5-120°( sample H), and 2.68 g of 1,2,4-tribromobenzene, mp 43-43.5°(sample I). Both were recrystallized from 95% ethanol.Counting Procedures. A liquid Geiger-Muller tube (20th Century Electronics, Type M6H) was used. Flatness of the Geiger plateau between applied voltages of 410 and 500 V was established using a 32P sample. Also, the counter was shown to respond linearly to the amount of 32P in the sensitive counter volume (about 8 ml). For 82Br counting, weighed samples were dissolved in an 80% absolute ethanol-20 % acetone solvent, which was then washed into the counter. The solution was made up to 8 ml, to a mark on the counter. For counting the dibromobenzoic acid samples, absolute ethanol was used as solvent. At least 20,000 counts were recorded for each sample. All samples were recrystallized to constant specific activity. Counting rates were referred back to an arbitrary zero time, the time of counting sample A. Other count rates were corrected to zero time9 by means of the first-order decay formula with attention to the 35.3-hr half-life of 82Br. Background counts were about 60-100 cpm, and appropriate corrections were made.