of the niincrnl ns far west ns Aluniblcs. The oro occurs between n dolomitic conglonicriitc nncl iydcrlying c:irbonifcrous limcstonc; the nnglo of t l ~p is 3 2 O N., frequently follorving cracks nnd joints in tlio strata. Altliougli or0 wns forlncrly raiscd in largo quantities from Trccnstlo Bl!vyndy, G:utl!, niid Llnrihnrry, to-day the only m n o working IS that of L1:inhnrry. pondcrnting niiiiernl is not limonite, but g d E (Fc,O,.H,O), the observed rntio of Fc,O, to I1,O boing very nenrly 1 : l . Somo of the oro vcry closely rcseinblcs the ~~c l l -k n o ~v n Cumlicrlnnd kiclncy-oro in nppearnnco and is also found to be gotliitc. Regnrding thc origin of tlieso deposits, the author cxprcssetl tho view that the rcplnccnicnt follo\red the ciitrnnco of the iron from nliove nnd not from b c l o ~, ns 1:ns hccn thoirglit by somc. Espcrimcnt shows n rmrkcd rliffcrcnco. in Lulk brtween tho frcslily prccipitntctl o s ~t l n n ~i d t110 niiricrnl of 1csc;rr hydraiion. Analyses show thnt the -SOTTTNC: t u x At n meeting held on Fcbrilary 10, JIr. .J. H. noiiford prcsidiiifi, Sir \Villiniii l'opo gavu nn :~dclrcss on tho ficicntific aiipccts of colour photography (cf. J., 1920, 3GOn), :it tlic c~osc of which Mr. H. n. Riclimo~itl clcricrihtl his early csperimerits on the mnio subject. FATS AND FATTY ACIDS FROM HYDROCARBONS, ,Yptit/retic fatfp ucit~s.-~fetIiods for proclucilig futty acids niuy b broiiclly classified into two innin group, in tho first of rvliicli tile fntty ncids aro built up from 11ydroc:irbons of low niolcculnr weight; siich as ethyleno or acctyIciic, or nro truly syr~tlichiscd from Iiytlroc:irbons of high n ~o l c c ~~l n r wiglit b r menns ok known rcuctions. 111 tho second CIOSS a hydrocnrbon of n higher niolcculnr weight tlinn thnt of the fatty ncid rcciuirccl is tiubniittcd siniiiltancously to partial degradation and osidntion. I n this clns! paraffin wns or l ~i g l ~-h i l i ~i g iinturril hydrocarbons nro ubvioiisly avuiliiblo as raw niiiterinls.