Oct. 2G,lO2@ example, tho Gcrnian laiigungc ; and Inany must wish that thc schools, or those who iiiflucncc them, would take n different view of tlic relative cultural vnluc of thcsc two subjects. Proiii tlic qiicstions priiitcd a t tlic end of thc book, it would np1)cn.r that the Joint Untriciilation B o d is not wit,hout rcspoitsibility in tlic inattcr.
T. S. PATTERSOX TIIE PYROLYSIS OF
C A R U O S COMPOUXDS. I3J' C. D. IIIJRD. Ainericnn Chcniicnl Society i\Ionogrnpli Series. Pp. S07. Mew York : Chcniicnl Catalog Co., Itic., 1929. $13.50. The cliniiges which chemical substanccs nndcrgo on lientiiig haw long bccn n subject of sciciitific anti industrial intcrcst, nnd in tlic prcsciit nionograplt tltc author lias gat.liercc1 together nn ciiornioiis ainoitnt of inforinnt~ion regarding tlic beliavionr of cnrbon con1pounds ~d i c i i subiiiitiml t o variations of tenipcrnturc. EIc cmploys the coiivciiicnt and concisc tcrni " pyrolysis " to indicate sitcli chciiiicnl changcs, ns this csprcssioii covers nll possible alterations, including tlicrnial rlccoiiipositions, molcculnr rcnrrnngciiicnts, dcpolymcrisntioiis nnd polymcrisntions. An o~iciiing chnptcr on gcncrnlisntions sitggcsts tlint vcry frccluctifJy such rulcs rcgnrding the course of pyrolysis nrc niorc honoured in the I~rcncli tlim the obscrvnncc, nnd csplnnntioiis of high tcinpcrnturc reactions nre citlicr of tlic rid lioc .iiriet,y or very spcculiitivc. T h e entidytic effect of nintcrinls composing tlic wnlls of pyrolytic vesse~s cmtiot bc entirely left out of ncconnt, for " in tlicriiinl dcconipositions it is difficult to distingiiisli between the catalytic nnd non-catalytic." 'I'licsc comn1cnt.s are IJornc out I J ~ tlic cspcrinicnts tlcscrilml