ON HYDRO-AROMATIC C'OMrOl'NDS WITH SINGLE NUCLEUS. 



137 



coloration with ferric chloride, and caustic potash replaces the hydrogen 

 atom of the hydroxyl group by potassium, giving a salt which is stable 

 in aqueous solution, thus resembling potassium phenolate, and not potas- 

 sium ethylate. 



Dimethyldihydroresorcin readily gives a monobromo-derivative, in 



(CH,), 



.CH., . CO 



c 



\CH., 



^CBr 

 C . OH 



which the bromine atom is very stable towards alkali/ thus resembling tlie 

 bromine atom in an aromatic nucleus rather than in an aliphatic body. 



Wave-lemjth Tables of the Spectra of the Elements u.ncl Compounds. — 

 Report of the Committee, consisting of Sir H. E. ROSCOE (JJhair- 

 man), Dr. Marshall Watts (Secretary), Sir J. N. Lockyer, Pro- 

 fessor J. Devvar, Professor G. D. LivEiNG, Professor A. Schuster, 

 Professor W. N. Hartley, Professor Wolcott Gibbs, arid Captaia 

 Sir W. de W. Abney. 



Infra-red Arc Spectra of the Alkalies. 

 Lehmann, ' Ann. d. Physik,' t. v. 1901, p. 633. 



Wave-length 



7701-92 

 7668-54 



8513-26 

 7950-46 \ 

 7805-98 J 

 7753-58 \ 

 7626-66 I 

 7406-19 I 

 727701 / 



9211-86 \ 



9171-38 r 



8949-92' 



8766-10 



8527-72 



8082-02 1 



8019-62/ 



7616-58 



7227-46 



Intensity 



Keduction to 

 Vacuum 



A.+ 



10 

 10 



4 

 8 

 10 

 G 

 6 

 4 

 4 



6 



6 

 8 

 8 

 IS 

 6 

 6 

 6 

 4 



Potassium. 



I 2 08 



Rubidium. 



215 



211 

 2-10 

 2 07 

 2-01 

 1-97 



Cjesivss. 



3-5 

 3-6 



3-2 

 3-4 

 3-5 



3-7 



Oscillation Frequency 



12981-7 

 13036 7 



11743-0 

 12575 2 

 12807-7 

 12893-8 

 13109-0 

 13497-5 

 13738-1 



Crossley, J.C.S., 1899, 75, 776 ; Vorliinder, Annalen, 1902, 322, 251. 



