122 R caustic soda tho residunl fibre cnn bc worked up into chenp pnpcr stock. Bnotlicr biochcmicnl pnpcr, by G. J. Fowlcr nnd 31. Srinir:isiycr, clcnlt with tho indigo dyo vnt. Instcnd of hydr~,ulphito tlic Indinns add tho sceds of ' 6 cnssin torn to rcduce tlio indigo to indigo nliitc. Tlicso secds contnin n siilpliur protein nnd bnctcrin tlint fcrnicnt and produco I;~jdrogcn, which effects tlic cli:ingc of. tho indigo. l l ~e r c is also n bitter siibst:!nCo wli~cli acts :16 n sclcctirc nntiscptic rcstr:ilnilig tho growtli of other bnctcrin. RECENT DEVELOPMENTS IN THE ELECTROLYTIC PRODUCTION OF HYDROGEN AND OXYGEN. A. J. i t m : . 31uch of tlic plrint cniplo~cd up to 1913 for gciicrnting Iiydrogcn and oxygen by the clcctrolysis signed prior to 1903, nncl nltliough sonio iinprovelimits i n dcsign nntl cflicicncy wcro introduced during tho two or tlirco ycnrs bcforo tho ivnr tlic dciri:ind of t ~i c ~i l i c s for tiicse g:iscs was no doubt rcsponsiblo for niuch of tlic activity rccciitly dis-p1:rgcd in this brnncli of industrinl chcmistry. Tho cells on tho innrkct today, ninny of \vIiicli linro bccn dcriscd during tho last six ycnrs, tnny bc clnfisified :is bell, filter-press, or unit typo. I~ncli r d l is usunlly c:ip:tblc of taking 300-GOO ninpbres, and tho clcctrodcs nro plnml. ncnr together to cliniinish elcctricnl rcsistnncc. Apart froin tho filtcr-prcm bi-polar type, tlic tcndcncy lins bccn t o dovclop tho construction of flnt-di:iphrngni units of uuxiinuiii cnpecity w11icIi occupy n niininiuni of floor-spncc. T h ~o single units posscss tho :idr:intngo over tlic filter-prcss type that nny ccll in nccd of repair nirty bo cut ont of tho scrics witliout sto ping tho rcmiinder, w~icrens in tlic filter-prcsti tlic \vhoIc groiip must bo stopped while the rcpnir is effected. Bell Cells.-Undcr this liend rnny bo includcd nll noi~-dinplir:igin cells, for tho prcdoniinnnt idcn in this typo is to prcrcnt tho niisiiig of osygcn :ind hydrogen by encasing tho elcctrodcs in such n miinner that tho dischnrgwl g!scs aro dircctcd npwords t o their rcspcctivo ninins. Soinctimcs tho construction is unncccssnrily coniplcx, ns in the Vnrcillo cell (Fr. Pat. of 1905) and Tonininsini cell (U.S. Pat. of 1912), nnd otlicrs; but'tlio plant of tho Hydrogon, Oxygcn nnd l%nt Co., b n d upon Jnubcrt's patents of 1916, nnd tho Cliurchill cell (Pet. of 31. Cecrncrd of 19lG) nro of siniplo constructlon :ind rcnsonnbly cflicicnt. Ench of thcso colls givcs over 6 cb. ft. of Iiydrogcn pcr kw.-hr.; tho forincr 1 1 : ~ bcen pnt cloivn a t sovcrnl Frcncli factories, arid tho latter is USMI in scrcr:il Englifih works.
The principle of tlic Jnubcrt cell is shown in