672 KEPORT— 1887. 



When a-pyrocresol is slowly distilled over a very long layer of hot zinc dust 

 in a ciuTent of dry CO or hydrogen, a soft, yellowish mass is formed, strongly- 

 smelling of anise-seed oil. By distillation with steam this yields an oil identical 

 with that obtained by reduction in the wet way, and a solid residue consisting of 

 unaltered pyrocresol. 



No dehnite views regarding the constitution of the pyrocresols can be prof- 

 fered at the present stage of our investigation, hut we may safely draw several 

 conclusions from the results so far obtained, more particularly in the case of 

 a-pyrocresol. Taking the empii-ical formula CjII, ,0 for granted — and it must in 

 the worst case be a very near approach to the truth, as only the hydrogen might 

 be slightly more or less — the chief point to ascertain is the position of the oxygen 

 atom. The absence of a hydroxyl group is shown by the fact that acid chlorides, 

 COClo and PCI,, as well as alkalis have no action upon the body. Hence the 

 oxygen atom must be directly linked to carbon, and this admits of two possibiUties, 

 viz., a carbonyl group or no carbonyl gi-oup. The presence of the CO group 

 would impart to the substance the general character of a ketone, but, unlike the 

 ketones, it does not under any circumstances and experimental conditions combine 

 with hydroxy lamine or Fisher's reagent — and the same applies to y- and )3-pyro- 

 cresol. The absence of the carbonyl group is reudered still more probable by the 

 circumstance that no acid oxidation product could be obtained, and that upon 

 reduction no disubstituted methane — viz., an isomeride of ditolyl methane seems 

 to be formed. From all this we are led to believe that a-pyrocresol and its isomers 

 are anhydrides similar to diphenyl ether, aud that they consist of two chains held 

 together by an oxygen atom — thus : 



C,H,C>- 



As to the exact nature aud .structure of the two chains, aud the relative position 

 of the oxygen atom joining them, we cannot at present oiler any opinion, until we 

 shall have more closely studied the reduction products aud tlie dichloride obtained 

 by PCI-. The investigation of these and other derivatives is being proceeded 

 with, and, we trust, wUl soon lead to decisive results. 



9. Ajyparatus for Ihe Examination of Air. By Dr. Ransome. 



10. Ajiparatus for demoiisfratinr/ the E.vpJogioii of Xitro-Ghjcerine. By 

 P. Bkaham, F.C.S. 



