348 STEWART-THE DETECTION, &c., OF DABlN.AR RESIX I N KAURI RESIN. [April 15, 1000.

Professor Wm. H. Brcwcr, Yalo Unircrsity. Professor 11‘. Gibbs, Hnrrnrd Univcrsity. Profossor Clins. F. Cliondler, Coliimhin University. Professor Im Ecniscn, Johns Hopliins’ Uiiircrsity.

I n tlicir lcngtliy nnd thorough report tlicy gnrc csprcssion to tlio following conclusions :- “ TI10 stnrcli sngnr thus iiindo nnd sent into coiiiiiicrco

is of cscoptionnl pnrity nnd iiniforrnity of composition, nnd contains no injnrious substance. l‘liougli n t liest liaving only nbout two-thirds tlio swcctcning poircr of cnnc sngnr, yet stnrcli srignr is in no wny iiifcrior to cniic sugar in licnlthfnlncss, tlicrc being no cridcncc before 1110 conimittco tlint innizc stnrcli sngnr, citlicr in its normnl condition or fcrnicntcd, lins nny dclctcrioi~s cNect upon tlic system, own wlicn takcn in Inrgc qnnntitics.”

Altlioiigli tlic corn prodiicts interests wcro forcniost among tlio food iiinnnfiictnrcrs of this country in seciiring tho cnnctniciit of n Niitionnl Purc Food Lnw, iind nltliongh tlicy spciit lnrgc siinis of iiioncy in improving tlicir pro- ccsscs, so ns to mcct cvcn tho strictest rcqnircmcnts of food Inws, tho industry found itself, iis recently ns lnst ycnr, fncc to fnco with tlic grnvc situntioii tlint nftcr it lad cstnblislicci tlio Iicnltlifulncss niid wholcsoincncss of its products, tlic wry nnmc of its principal protlnct wis now mnclo tlic snbjcct of nil nttnck. It is Iiiird to nndcr- stnnd why tlio nnmc “ Corn svriip ” slionld not giro satisfaction to crcrybotly ; it cl.rtninI sntisfics t ~ i c con- sumer, w1i0 is tho principnl p r t y to l o considerc!, its it tclls hiin csiictly of \rIint tlio prodnct is mndc. TI10 ninin reason ndvnnccd uliy this nnmc irns not considered propcr wns, tlint fn r linck in 1S12 cspcriiiicnts acrc I~ciiig con- ductecl in this country for tlio purposc of cstncting from tho stnllis of tho corn n syrnp bclongin~ to tho sncrosc class. It would mcm tlint sncli n protlnct, if nctiinlly niudc, should bocnlled n ‘‘ Corn stalk sjmp,” ns tlio nnmo “corn ” npplics only to tlic grain niid not to tho stiilks. “ Corn stnlli syrnp ” wns tho nnmo npplicd to it in tlic ciirly rcports of tlic Cominissioncr of l’ntcntu, nntl tho rcry fnct tliat tlic cspcriiiients \rcro condnctcd orcr GO years ngo, qnd did not lend to niiy conii~icrciiil sncccss, clciirly provo that t h y cnnnot bc considcrcd other than nbnndon~l crperinicnts. It is gnitifying to note, lio\rovcr, thnt tho highest iintlioritics nndcr tlio Food nnd Driigs Act, nnmcly, tho Secrctnrics of Agricultirrc, tlio Trciisury, nnd tlio Dopnrtmrnt of Coninicirc nnd I~boi ir , nftcr n most cnrcful czuminntion of nII tho tcstiiiiony snbniittcd in nn oflioinl promulgntion, dcsignntd ns “ Food niid Drng Inspection 887,” proclnimcd corn syriip ns tlic proper nnmc for tlic product, obtnincd by R partinl Iiydrolysis of tlic stnrcli - - . - - Of tho corn. ~I‘liilc I linrc eiiiplinsisccl tho importnnco of corn syriq) ns n food nrodnct, I do not wisli to ncrlcct tlic teclinicnl iiscs to wIiicIi corn syrup is put. They nrc inniinicrnbIe. nnd it wonlcl cscccd tlio scopc of this nddrcss w r c I to cnunicmtc tlicni. I do widi, Iio~rcccr, to cnll tho nttcntiori of niy brotlicr-cliciiiists. cngiigccl in tecliniciil pursnit. to tho grcnt rorsntility of this iroduct, niitl I fcel tlint it is not its yct fully npprccintcd. ns pcr~inp too littlc wns Imown nboilt its incrits. npnrt froni bcing ii food prodnct. Tho corn ~~rorlucts interests nlwiys linrc ninclo it n policy to cncoiirngc and foster cspcriiiicnts, looking to n grcntcr oonsuinption of corn syrnp nnd corn siignrs in tecliiiicnl f i o p

1110 corn protlncts industry hiis uniicrgoiic grciit cliiirigcs. Fnctorics linrc conic niid fnctorics hnro gonc. \J’Iint onco \\m considcrcd tho bcst, wiis liitcr found to bnrcly in& tho nvcrngc. Wlicro oiicc n GOO-bnslicl norlis wns lookctlirpoii mitli iiwc, n fnctory grinding 15.000 bnslicls iironscs no spcciiil nttontioii todny. Tho fnctory biiilt in Cliicngo in 1882 IV~IS n 111iitliii11rli of tlint city ; it wns nlso loolicd lipon ns n iiiorlcl pliiiit ; it wns pcrlinl~s tho only fiictory uvcr bnilt in this conntry, linring n liciglit of 1.i storeys. Tho iden go~*crning tho urcction of it \\orlis of siicli l inw lioiglit wns to opcriito it upon t ~ i u yrnvity plnn : tint E, tlio corn wns clcriitctl to tho to11 floor nnd from tlicrc grndu- nlly worltcd its wny docrii to tho ~viirclionsu rind sliippiiig Boors, from wlicro Llio finislied goods wcro londcd into tho cnrs. It lins bccii niiiply dcnioiistmted, Iiowcrcr, ?hiit t l i i H rnotliotl cnn no longur bo considcrcd good cngincurnig, n t lcnat not in o w industry. !rho striiin on tho building, tlio woar nnd tcnr, nro too grcnt, niitl tho cost of ninintcn-

ancc beconies too budcnsomc. Thus it linppcned thnt within tlio lnst ycnr tho old “ refinery,” ns it wns known, \rns razed to tho ground, and witli it is goiio n pnrt of old Chicngo nnd memories of tlnys of toil nnd effort, of failure nnd SIICCCSS. “ Sic transit glorin m u d i ! ”

All tlint remains, nnd only for a littlo wliilo longer, arc tho tnll sniokcstncli, rcnchiiig nliiiost 250 fcct into tlic skies, and n few minor buildings, in which soriic of the spocinltics nrc still being mnnnfncturd.

I n its stcnd, Iiowcrcr, riscs Plimnis-like, n ~icw indiistrinl city on tlic bnnks of tlic Diniiingc Cnnal, nliich forms R link of tlic proposed vntcrwny bctaccn tlw Orcnt LRl;cs nnd tho Gnlf of Jlcsico. \Vlicrc, orily n ycnr ago, tho conntry in tlint section wns still given orcr to fnrniing nnd \rns fnll of chnrniing \roods, tho situation to-dny is w r y diflcrcnt. Tho prniric is bcjng rapidly trnnsformctl into tlic sent of n great indnstry. rlio trolley- cnr, tlic grcnt ciriliscr, 1111s nrrirctl on 1110 acric; con- trnctors Iiiiro bcen n t work di ging niid cmnmting, bnildirig fonndiitioiis nnct ttinncls, an9 grnclunlly t1ic clinos ticgins to nssnnic sliapc. Hnge stccl l~nildings risc in 1110 diffcrcnt parts ; tlic lntcst stylo of building-rc.c~iforcecl concrctc. can be seen rill over. Grcnt difficnltics lind to 1)c cn- countered, ns, for iiistnncc, tho niising of the innin l i y of tlic Cliicngo nnd Aton ltnilrond n heiglit of ten fcct 111 order to rcncl~ tlic tloclis sitnntccl on tlic Dminngc CnIin!. A ricw from tlic Administmtioli nnilding slions tlic rnstncss of tlic cntcrprisc. This plnnt, \rhich led to tlrc founding of n ncw city, ciillcd “ Brgo,” \rill liacc ultinintcly n cnpncity of G0,OOO bnslicls of corn n dny. It will corer on nrcn of 1% ncrcs, ancl mill gicc cniploynicnt to tlionsnnds of iiicn. It is thc cliinnx of tho dcrclopmcnt of tlic iiidnstry of corn products : a proiid iiioniuiicrit to American cntcrprisc, Anicricnn skill, Aincricnn ingcnnity. Anicricnn ~~crscrcrnncc. I t is n nioniinicnt to tlic liceti foresight of tlic progrcssirc mnnngcmcnt of tho “ Grcnt Aniericnn Industry of Corn l’roducts,” nnd is no lcss n iaonuiiicnt to tlic pionccrs of this industry, who linrc mntlc sncli crolntion possiblc. If n nicniorinl tablot were to bo plnced on one of tliosc ningnificcnt buildings, nniong tlic l~nnies inscrilml tlicrcoii would bc found tlioso of H. C. Hiimplircy. Dr. Cicscckc, Tlioiiins Cnnnt, my lnmcntccl fricntl nnt l co- worker Lcc llnrrison, Clinrlcs Pope, Dr. Firiiienicl~, tlic IInnilins, tlic Jhttliicsscns, nnd, nborc nll, tho nnmc of tlic nuin in wliosc honour wo ilrc iisscinblcd to-night, Dr. Arno Bclir.

Soottish Section.

DAVID J. PLAYFAIR IS TlIE CICAIII.

THE DE~EUl’IOX AXD ESTDIATIOX OF DAJIXAR ltESIN I N KAURI RESIX. BY SAJIUEL STEWART, F.1.C.

Dunininr rceiii, or gr im duniniar is tho prduct of ccrtnin spccics of Dasti,iuru niid I lopw, wl~icli grow in Soutliorn India, Borneo, ctc., niid is obtnincd froni livirig trccs. It coincs into tlio i i i i ~ l i ~ t in rnrions forms, tho fuior qunlities Iicing in largo picccu of n clcnr yollow, and otliors brownish or rcddish. Tlic lon.cr grados nro iii tlio form of rains.

T~ic c~nssificntion of sonic of tlic resins is wry dofoctiro niid confusing, ns, for csnniplo, 3lnniln copnl from I‘atcria Iiidico is li~io\\m ns “ wliitc dainiiiar ” niid knnri copd from Durwiarcc Aiiutrulie is litio\\*~ps “ Now pnlmd daminor.” !rlicro nro tliiis clnsscd ns dnmninr tlio produots of widcly tliNurcnt trccs mid tlio rosins posscss rcry difforcnt propcitios. In a pnpcr by Robcrt D. Thoinson, ALD., rcnd at a

mooting of tho l~liilosopliicnl Society of Glnsgorv* 011 liitli Nnrcli, 1843, it is mciitio~~cd that s~~ocimcns of both ~~

Transoctloue Vol. I., p. 1%.

VOI. XrCVm., h’o. 7.1 STEWART-THE DETECTIOX, &C., OF DA3ZJWR RESIN IN KAURI RESIN. 349

trccs, Damniara dnirtralir and I). orienfalia mro to bo soon in thc Botnnic Garden thorn, nnd ho cvidcntly loolid upon tliom ns giving rcsin of similar qunlitics.

Kauri resin, or p i n kuuri, is tho prduco of n conifer, which is indigonoris to Xcw Zcnlnnd, nnd may bo ‘‘ Bush Gum’’ from living trccs, but much inore gcncrnlly is “ Fossil Gum,” dug out of tlio ground mlicrc old trccs onco flourished, but now lio buried niid clccnycd. It COIIICS into tho mnrkot in n grcnt vnricty of qunlitics rnnging from largo clcnr picccs through nll grdcs to groins nnd dust. In tho lowcr qunlitics n considornblo nniount of irlint is known as “ S m m p Gum ” is present, bcing tho original rosin greatly nltcrcd by tlic nction of air nnd water into o oroits mnss.

IEt is practically impossible to clistinguisli by ttic nppcnr- nnco bctwccn sonto of tho kinds of dninmnr niid knuri, cspccinlly bctwecn tho kniiri chips arid md dniiimnr. Both resins arc used in vnrnisli Innking, but tlic itec of kauri gum ns an ingredient of tlic “ ccmcnt ” for linolcutn mnniifnntnrc is tlint with ivliicli tho writer is concerned. Tlic relativc values of tho vnrious grndcs of kauri for this purposo will not 1 ~ 3 touclicd upon in this pnpcr, nor will tlic qucstion of whcthcr dniiininr or otlicr rcsins bc inoro or lcss suitnblc for strcli n pnrposo Im discussed.

Tho knuri used for this puq)csc is gcncrnlly onc of tho lowor grndcs, ns trnnspnrciicy, Cc., ricccssnry .in rnrnisli making. nro not csscntinl. It cotisists of picccs of varying sizcs from dust upwnrds to chips. In ordcr to obtnin ns fnir n sninplo ns possiblc for nnnlysis, n qunntity of nbout 1 lb. is tnkcn nnd pnsscd througli thrco sicvcs of different mcslt. It scnrccly ninttcrs wlint tho osnct mcslics IJC. but. so ns to gct uniformity, picccs of tho wiro clot11 used in tlic t r d o for Rortinl* out into diffcrcnt grndcs wcro procured nnd nro used Por this purposc. Tlic proportion of tho four various grndcs thus ohtnincd is nsccrtnincd by wci lting nnd cnlcitlnting to pcr cent., and thcn 10 grniiitnes in tficso proportions wvciglicd out arid groutit1 togct~ier.

About four ycnm ago tho question of tho possibility of dotccting tho ]mscncc, nnd if possiblo, ostininting tho proportion, df dninninr rosin in kauri rcsin kcnnic nil tmportnnt onc. ns i t wns suspcctcd tlint n Inrgc pirccl of guni just rccoivcd wns not gcni~inc knuri : niid tho grcnt difforcnco in prico-ubout €GO per ton for knuri ngainst nboiit 920 for clnininnr-irns R scrious 0110.

A considcrablo nniount of inforinntion Rs to tho soiirccs axid gcnornl proprtics of guni resins of nll kinds is to IJO found in vnrious dictioiinries nnd tcst books, inom cspci. ally ns to tlicir uses for vnrnisli innking, nnd tho nction of solvcnts upon tltciii, tho lnttcr Iming gcncrnlly given ns “ solublc,” “ partinlly solublc.” or “ insolublc,” no indicn- tion of tlio pro~iortions of insolublc nnd solublo bcing given. Spccific gravity niid iuclting points nrc nlso givcn in so1110 cnscs, but, nltliougli tho lattcr rnrics con- sidcrnbly for tho vnrious rcsins nnd niiglit bo uscful to so1110 cstcnt in nssisting to idciitify dcfiuiito rcsins,cspecinlly ivhcn in u conipnrntircly pucc statc, it can Iw, of littlc usc in dcnling with niiscd snitiplcs.

A bcttor litic of invcstigntion wns indicntctl by such workcrs as Mills*, who recorded tho rcsults of his cxpcrimcnts on broiiiinc absorption nncl potnsli nbsorption, as applied to resins. Sincc tlicn u great itttit ikr of dctcriiiinntions of ncid, si iyil imtion nnd iodino vnlites linro bccn tlutcrniinctl by . cliniitlt nntl Erbnn, \\’illinnis, llottlcr, Diutorich, kc., ntitl niny bc found recortlcd in rnrious piiblicntions nnd collcctctl in n forin siiitnblc for. rcfcrciicu in “ :innlvsis of resins, bnlsunis, nnil giiiii Tusins,” by K. DicturicL

Confining nttcntion to tho question of diiTcrcnccs botirccn dninninr nnd liniiri rcsins, n senrcli IVnH nindc tl1ro11gl1 nll nvnilnblo litci~ititro on tltu subject, ntid it wns found tlint no sntisfnctory inctliod of tlutcrniiiiing tlio prcscnco, and still lcss tlic proportion, of thcso resins iti nn iinknown niistiiro ~irt.scntctl itself. Tlius, ciltliougli IC. Diutcriclit giws 20-30 ns tlic ncid nilnibor for tlnnitnnr. rind Willinins$ 6-42 ns ~iotnsli nbsorption (hot) for Iiciiiri i i s n ninst 2-83 foi’dnmnini*, rind 13042 ns iodino nbsorptioii for Ttniiri ns ngninst 00.40 for dnnimnr, nntl ~ippur t nntl

.

Tlils J., 1865, 07, nud 1880, 222. “Ms J 1807 820. i 11’1118 i:, ieoti, 1168.

Rcissigcr. ncid caluo : knuri, 64-81 ; dnmmr, 33-35 ; Lo\~lio\vit@,t on tho other linnd, givcs

For knurl: ncld vnluc 37-30, snp. v. 53.84 6 1.V: 90.99 For dnniinnr: ,, ,, 35-22 ,, 32-13 6 I.V. 1’27.5.

which shows thnt such inothods of distinguishing these resins nrc rcry unccrtnin. \\‘orstall$ goes moro thoroughly into this dctcrniinntioii, and gircs his rcsults as follows :-

TADLE I.

Dnmmnr. lumps. dust.

Acid vnluc ............ 24 to 55 Iodine rnlua .......... 1 1;; 1 ’$ 1 1% to 103

thus recognising tlio iniluciicc of osidntion on thcso substnnces. A sninplc of rock dntntnnr from Burma t c s t d n t tlic Impcrinl Itistitutcs shoacd ncid vnluo 31.5, snp. wluu . 37.1, niid it wns n o t d tlint i t wns c~ttipl~tcly solublc in turpciitino nnd pnrtinlly solublo in nlcoliol. Aiy iodiiio rnlucs which tho witor has dctcrniined linrc been so crrntic tlint ho prcfcrs not to rcfcr to tlicni. As tlieso fiprcs poiiitcd to g e n t 1111- ccrtninty ns to tlic dcfinitc dctcrrninntion of whcthcr a snmplc of resiii could bo ccrtificd n s knuri or dnintnnr or nil ndmisturc, no stcps wcro tnkcn to follow on thcso lilies. This bcing so, i t wns wen thnt tho wliolc quostion noitld linvc to bc gonc into dc nmo, nnd tho most promising linc of inrcstigntion \VIM tlint foitndcd upon tlio obscrm- tion tlint 11cnr1y nll workers noted tlint sonio solrents ncted :diflcrcntly on knuri niid dnmmnr. In turpcntino, for csnniple, dntiimnr wns itotetl ns solublc, nnd kauri. often confused with tho tnic dnuinnr, is somctimcs incntionetl ne pnrtinllr soluble, or insolublc. In nlcohol i t wns noted thnt knuri wns soIubIo nioro or ICSS coinpIotoIg nccording to tlio strength of tho nlcohol, whcrcns dnmmnr ivns “ pnrtinlly ” solublc, ntid so 011 with otlicr solvents. In order to cnrry out this itivcstigntion, sninples of

rccogniscd gcnuiiicncss wcro obtnind‘ nnd about 100 grntntncs ground nnd pnsscd through n .IO-incsIi siovc. Tlic suspected snmplc \vns siiiiilnrly prepnrd. Working first on tlic gcnuino resins. 1 gr. of cncli wns slinkcn up (cold) with 20 C.C. of tlio following solvents, nnd tho rcsults nrc :-

TABLE II.

Gnsollnc. I Bcnzol. I Turpcntlnc (Amcr.).

Knurl ...... Lnrgcly sol. Prncticnlly insol. Dnmninr .... Senrlp nll sol. I’nrtinlly sol.

111 nttctiipting to tnko ndrnntngc of tho nicirkctl t l ihcnco in Idiuvioitr toivnrds turpctttinu tho followiug cspcri- iiiciits wcro tiindo :-

T h o grouud sniitplcs wcru first Itcntcd to 100’ C., thcn 1 pr. filinkcii 1111 with 20 C.C. Anicricnn turpcntino in grniliiiitctl tribes, nntl nftcr sct thg. 10 C.C. of tho clcnr liquid tlrn\rtt off, cvnp. nt 100’ C., ndtliiig ctltcr nnd tlicn nbsolutc nlcoliol, nnd tho rcsitlunl cstrncts wiglied :-

TADLE 111.

Knurl. . ............................... 00.0 Doiiiinnr .............................. 140.0 Suspcctcd aamldo ...................... 101.0

It ~ v n s observctl tltnt tho titrpcntiiio lint1 l~ccomo tusiuified nud WIIR not csl)cllcd n t this tuui1)crnturu. Tlio imretrde in wcigltt of tho cstrnct from tliu suspcctcd ~ n n i ~ ~ l e , in r i u w of tho very gront incronsc in tho C n R O of tliu clniuninr, is notcwortlty ns prolinbly intlicnting tho prcsci~cu of tho lnttcr rcsiit. Ilnd this snniplo bccn pure linuri, it is to bo cs~icctcd thnt it ~vonltl ltrivo gircii

Resulta pcr cent.

Tlila J 1000 1153.

: Tlih J., 1003, 1130. OTIils J., 100I, 551.

t wtis J:: iooi: 371.

n figiiro less tlinn 100. Tho mothod is obviously qiiito iisolcss, howcrcr, but is givcn hcrc, ns i t wns in tho course of cnrryirig out this cspcriiiicnt tlint tho nicthod finnlly ndoptctl wns discorcrcd. It xvns noticcd thnt on ndding tho etlior nll tho estrncts dissolved to clcnr solutions. but thnt on ndding tho nbsolnto nlcoiioi n copious whito

Perccntneeof dntnninr (enlculnted) . . . . . .

JInreli-July, 1005.

ndding n littlo sbsoluto nlcoliol to tho rcsiduo, nnd drying n t 100” c., tho aliito siibstnnco is obtained. It is cstromcly solnblo in clrloroform nnd, nfter ndding tho nlcoliol to tilo cstrnct, i t v c y soon renchcs n constnnt irei lit by

nil bocn obtnined br tho process just described. licnting ns nbovc. rlio results shown in ‘l‘nblo I\. f: ltnvo

85.08 81.04 180.84 80.00 0P24

4.80 \ 0.48 1.00 7-84 38.50

4.48 1 0.28 3.12 2-08 0.08 5.04 1 0.20 6-44 3.48 0.12 ----- 100.00 100.00 ‘100.00 100.00 100.00

0.00 I o m I 3.20 1 1 20.331 - I I .I ~ _ _ _ _ _ _ _ _

1 reb. I Jlur. /I 1000. 1007. Jan. 1000.

pno with tho suspected snmplc. nnd tione with k i d . rliis wns confirninl bv trcntin soiiio knnri nncl tlnrnmnr wit11 ctlior iind tlicn ;idciing i%soiuto nlcoliol. wlicn tlic Icnuri roninincd clcnr, tho dnintnnr gnvc n inrgc wliito procipitnto, nnd tho suspected snmplo n distinct precipitntc. Tho prescnco of this white substnncc, insolublo in iilcoliol. in tho dnmntnr rcsin ntid its nbscnco in tho linuri pointed iuimistnkcnblv to a Iirobablo method of dctccting tliu fornior in ndtnistnro witti Iiniiri. AII tho scilnples of linnri nnd dnmmnr, which hnd bccfi rccoired n t rnrious tinics 11s specimens, wcro tostcd . in this niniilicr, nrid roitlroict exceeplioit tho rcsalts wero tho ssmc-tho knnri rotnnincd clcnr nnd tlio clniiiiiinr gnvc tliu wliito curdy prccipitntc. This rcnction w s tcstcd by npplying i t to rnrioiis misturcs of dnnimnr ntid knnri in litlowti nnd iinltnown proportions, nnd in ercry cnsu tho prcscnco of dnniiiitrr coulcl be decided dcfinitcly. l\’licn trying to npply this rcnction to n qiinntitativc cstimntion of tho mnount of whitc substrinco present it wns found tlint cliloroforin wns n itinch botter solvent tlinii ctllcr, tho clnmninr clissolving coinpletcly nnd nipidly in it, nnd tho lintlri giving 11 pasty lntiss 11s with ether. Tho process 11s tlicn carricd oitt nnd still in uso is ns folloas:-2.6 gr. (I\ convcnient qnnntity) of tlio soniplo of resin, finely ground, is wciglictl out in 11 tnrcd, plcntccl, filter pnpcr, tho opcn cnd ticd up with titring, plncecl in II Soslilct tubc, the spnco bcing fillcd up with stnnll gliiss bnlls (to ndniit of 11 iiiinitiiuni quitntity of solvent Iwing used). ostrnctcd i t i tho usitnl wny with nbsolntu nlcoliol, nnd tho ostrnct collcctcd in IL tnrctl flrisk. Aftcr sorcrnl hours it will bo foimd tlint, if tlio sninplu be pitro Iiniiri, tho filter p p c r will contnin only orgniiic nuittcr (rcgotnblo libro, kc.), nrid mincrnl in~\ t tc r (clny, ko.). By drviiig nti(1 wcigliing tho filter iind contcnts iti id tlien igniting niid weighing tho niincrnl ninttcr tlio 1)crccntngo of tlicsc limy bo foiind, nncl tho clillorcnco noted 11s Iiniiri resin (pure). Of coiiiw, tlio alcoliolio cstrnct iiinv bo licntctl o t looo C. nnd ~rvcig~icd, bnt, 11s II rnrinblo’ ninoiint of rolntilo mntturs nru ospollcd, this is not inoro accurnto tlinn ostiiiiiiting i t by dilTorotico. If tho snmplo bo rlnniniiir, or n misturo coiitnining iL, i t will bo found that tho filtor p n p r will contnin, besides tlio rcgotnblo nntl minornl ninttors, son10 wliitu pnrticlcs. In this cnso nll tlint is 1leccssnry, nftur first driving ON nt 11. gentlo I lCJ l t tliu iilooliol nclhoring to tlio filtor, is to roplnco it in tho Soslilot cippiiratus nnd ostriiot iritli oliloroform, collccting tho solution iu n tnrcd ilnsk. On distilliiig olf tlio oliloroform,

Aftcr tho results from tlic firat sntnples of linitri nrid dniniiinr were obtnined, n misturo of tltcsu two idcnticnl yuniplcs IYIIS niiiclc nnd iinn1yw:d by this proccss. Tliu result, \rliicli wis w r y mtisfnctory, is shown in coliinni 3. As i t wns lilccly tlint dilTcrent lots of dninmnr woultl contain vnrving nniortnts of this wliito substnncc, it wns iicsirnblc, whcnevcr possible, to obtnin ljonio of tho notun1 dnnininr resin foimd t o IJO present in tliu suspected snmple, n n d in order to do this, tho following Iiietliod wns iidoptecl :-

Soiiio of tho Inrger pieces of tlic resin wcrc picked out, niid ench tested by rnbbiiig with II drop of cliloroforni on n glnss plntc, iintl on nclding n drop of n1)soIuto nlcoliol it WJIS tit oncc SCCII \vlictlier tlic picco gnvc tho dniiiiiiiir ro- nction or not. l\’iicn n sullicicnt qunntity wis thus obtnined. tlio pieces icere ground 111) niid nnnlyscd ns iisnnl. Broni tliu pcrccntngc of wliito siibstnnco fonnd tho ninotint of di~iniiinr in tho sample w w ciilciilntcd. The figurcs for tlunitnnr rcsin givcn in coliinitis 4, ti, nrid 14 wcru t h i s nsccrtniiictl. Tho lainri iuitl dnnininr picccs from sntnplo 4, tlio nlcoliolic estrncts from ti nnd i, tho cliloro- form cstnicts (wliito dnnimnr substnnro) froni 2, 4, 6, 7, nntl I!? nro csliibitcd. It is obvioits, of courso, tlint this. mctliod is not n1)plicnblo in tlio cnsu of grnin or clnst gnni. In siicli C I I S ~ S , if tlnnuiinr bo cliscorcred, it is sitflicictit to consider diiniinnr resin 11s contniniiig 60 pcr cent. of tho whito substnncc, niitl by this nicnns tho ~icrcentngo of nclnltcrntiori is inost liltclg undcrstritcd. Tlio figiires for dnmtnnr resin in coliinins 8, 9. 10, 11, 12, niid 13, w r o so cnlonln tctl.

This niothotl of testing is conrenient for tliu mpid idcntilicntion of snmiilcs. Hccctitlr 17 mni)lcs of 1111 griidcs of irniiri nnd -12 PniiipIcs df dnnininr- woro tliiis tcstccl, rind in crcry cnso tliu rositlts \rcro ns nntioipiitctl.

A tliird mothod of applying tlio test, wliioli tiorron 11s n qtinlitntiro one, nnd rilso for cstimntitig siiinll crniounts of tlnmmnr (niitlor 1 por coiit.),is enrriotl ottt nn follows :-

0 5 61.. of tho fiiicly groiiiitl snm )lo is trcntctl in II porcoo- Inin oriiaiblo by. R t irriiig . i l l ) witL u\iloroforin, filtoriiig tliroiigli it sninll filtor into a test ttibo, wrriliiiig OIICO niid tlion ntltling nbsoliito nlcoliol. If tho snni )lo coiisists of linnri oiily, t ~ i o tiolutioti will roinnin por/octly olonr, biit if clnmninr bu prosont it clottdincss or prccipitnto will nppcw nccortliiig to tho nnioinit, ‘1’0 rondor thiH inot,liod nvnilnblo for ostimnting xninll ~~orcontngos of dnnimnr, n mist.itro of linnri imd tlitnitnnr rodin iti propiti*od t o ooiitnin 1 poi- cent. of tho wliito ljnbstniioo snd 011

Vol. XXVIII., XO. 7.1 PROCTER-THE ACCURACY OF THE NETHOD OF DETANNISATION, gic. 351 - --

quantities of this being wcighcd off nnd tested in &bow manncr IL fiiirly ncciirnto cstiniation of tlic clammar prcscnt in nn unknown mixturc can bc inndc by conipiiring tho iriiioiints of wliito precipitates obtained. In this connection two insttruccs can bc cited, 0110 of wliicli giire it precipitsto equnl to that iron by 0 3 of tho 1 per cent. mixture, or 1.3 per ccnt. 5nniiiiiir, and t ~ i c ot~ier cquu~ to 0.06 mistiire, or 0.2 pcr ccnt. It wns ssccrtiiiried siibscqncntly tliirt it wiis qiiitc probirlh thirt i i xniirll coiinter siiniplc of drrriiniiir l~atl been tlirown iunongst tho lot of kauri in tho wnrclioiisu.

Tho tlitinks of the writer iric duo to JIcnm. Xcliiicl Bnirn s; Co., Ltcl., Kirkcnldy, in wliose lnboriitory the iiircstigirtioii was miitlc, for tlicir courtesy in prmitt ing tliosc rosnlts to bc piiblislictl. . ___ __

Yorkshire Section.

THE ACCGHACT OF T H E AIls'CIIOI) OF D I W A S - SISATIOS OF TIII.: I ~ ~ I I ~ I { ~ ~ ~ ~ ' I ' I ( ~ S ~ \ ~ , ASSOCIA- TIO.\T OI? LEXrHEIt TRA1)lfS CHICJIIS'J'S.

DY IIESIlY 11. 1'IlOCTEIL

&nsidci?ible doubts linvu hen tlirown on tho iicciinicy of tlic prcsent ofliciiil nietliod of the I.A.L.T.C. 1ig h o l m Cormiin ~Iiciiiitits, iind cspeciiilly b tl iu Asswintion of Gerniiiii Bstrnct >~nnufiictumrs. \ d o iuivo consistently opposed its ndoption,' nnd by iinplicrition linvo tlirown doubts on tlio botio 5des of tlio tbiicriciin tintl En 4sli clicniists who clninied to obtain esnct rnsults. kiicli conipliiints woro porliiips iiiiturnl with nil rrniiccnstonicd process. i d uspocinlly with nn oinpirical onc wlielu nbso- luto iidliorcncc to tho prcscrilition is cssentinl : nnd I linvo hoped tliiit, with espcriuncu, tho tlifliciilties, iind with theso tho objcctions of Ccrniiin clioniists woiiltl dis- iippcnr. This 1iop luis been liirgcly justified wit 11 individiiiilu. biit ns tho Gornuin Estrnct Jlnnufiicturers ninintnin tliuir iittitudc of opliosition, I feel tli i iL it is notv tinic. no t only to provo tliu ostrcnic ncciirucy of tho iiiutliod in cnpiiblu Iicinds, but to giro tho fnllcst ~iossililu details of tliu inenns 1)y ~vhicli this ciin bo obtiiincul.

111 tliu first ~iliicc I will clcnl with tho cliroiiiiiig wid wiisliiiig of tho powder, und tlio obtciining of bliiiik rcsiilts in whicli tho dry residue of 100 C.C. of water sl~iilien with the powdcr slioiild bu iintlcr 6 mgr., iis ~irescribecl bv tho rcgii~iitionn, n figiiiu w~i ic~ i sovcrii~ cliemista IIIIVC iisicrtet~ it w~is i n i p o d ~ l o to uttiiin. Tho following is ii full tlcmriptioii in detail of tliu mctliod adopted iii nry own laborittory for tliu dctcruiiniition by bliink tents of tl iu soliiblen in clironicd iiiid ~vnslietl Iiitle-powtlor.

TI10 Iiido-lio\vdor is \rciglictl, its ncidity iidjnstctl, rind cliromccl f w onu hour iiceortliiig to tliu I.A.IA.T.C. rcgulntiona.

Tliu cliromcd Iiidu-po\vdor is tlicn tlirown upon ii clenn Iiieco of lincn in tliu Iicrfonited vessul of it scruw-prcss.* or in ir fiinnul, tlio iortions rcmiiining on the sides of tho bottlu being wiislicd on to tlio limn wit11 t ~ i s t i ~ wiitcr. 't'lio liquid is cillo\vctl to diiiin nwiiy, rind tlio powdur i i n c l linun ivriiovctl from tliu p s s , aqucescd by Iiiind, rutiirned 60 .tho press, and 1iressiiro applied. Tho nioro liqiiitl roiiioved at this etago tlio quickor tho powdur is frcetl froin uliloridos, but car0 niust bu tukon tlint ~iressiiro iti not uppliud too sudduiily, or tho linon will Liirst. 'l'lio lincn with tho powdur is tliuii roniored, and tliu lirttur, roiiiaiiiiiig in tho liiicii all tho tini0, is woll brokon i i i i by rubbing tl iu alotli botwccn tho liauds and rotiiriicd to tliu mss, w~i io~i is f i ~ o ( ~ u ) witli t ~ i i ~ l c x ~ watur. ~ ~ i u powdur is t~ioroiigli~y stirrod witli n glsu rod until a11 tlio w t u r ]ins

*Tliu ordinury Oeriiioii fruit-press costiirg 16n rriid Iioldiug about 1 litru is found to bo very nutisfuatory. It is coi;vcnicnt to tiovo o w or two o! tliu. iiriier veasels varylug in sizu for dllfcreirt quontltlcs o! powdor.

r u n out, and is squcczcd again. It is w r y esscntinl to kcop tho powtlor woll stirred, otlicrwiso clianncls will bo formed, througli wliicli tho wntcr will run with w r y littlo washing ctfcct. This proccss is rcpoatod about firo tirno3, 60 0.0. of tho last portion of wash-water wliich can bo rcinovcd from tho powdcr by pressing bcing tested for oliloridcs. It is atlrisnblo nftcr liaving tcstcd tho washings, ant1 found tlicln to coniply with tho I.A.L.T.C. rcgiilations, to rivc 0110 more wasliing, bcforc tliu final squeezing to rciiicu tlic wotcr to t ~ i o nccwsnry quantity rcntly for woigliing. Tho washing proccss sliould bo continiious, and on no occonnt sliould tlic powdcr bc left to stand. A quantity euflicient for four analysts in cln~ilicntc (nboiit GO grnis. air-dried po\vder) can bc wnshed frcu froin cliloridc in nboiit 30 niiniites, provided tlic process is continuous. Tho powder is now l a d y for weigli- ing, nnd is tmnsfcrrcd from tlic linen witli n spotiiln to n biisin or othcr convenient vesscl for waigliing. Tlic Iiist truces of powdcr may bo ronioved by lioldirig tlio fonr corncrs of tho lincn to etlior nnd beiiting i t upon tlic bench. wlien tlio povdcr wi17 collect in tlio ccntm of tlio c~otli. Tho rciunining ~nnnipiilations nro prcciscly ns for tanning iiriiilvsis, biit iising 100 C.C. of distilled writer instend of tiuiiiiiig ~iqiior. TI10 followiiig ciiiiscs tend to too high rcsiducs wlicn

cnrrying oiit blnnks :- I. Itt ipuril ies i t& thc dialilfd rcufer ltsd.--'lho tlistillctl

wntcr slioiild Ici~vu no wcigliablo rcsitluc on evcipoiiitioii of 100 C.C. to dryness.

2. Soliible ttinttcr /rortrtlre hattils wlicn sqiieoring tho liqiiitl nwiy froin tho powdcr nftcr detiinnisiition. Tho ~ioivdor in tlic lincn miglit bc pressed iigninst tlic sidc of the fiinncl with n sliiitulii to oqml tho last of tho liqiiid.

3. Sdriblc tiiuiter /rottL litreti nsed nftcr finnl cliurning. Tliu clotlis sliould bo wnslietl with wiitcr iilonc, iiotliing in tlic nntiirc of soiip bcing used, iind fi~iiilly in distillud wntcr bcforo drying.

This lins cuiiscd scrioiiv orrom, and tlic kaolin slioiild bu tested

'

4. I t i t p r / e c t inaolirlilily 01 the knolin used.

uvnliomtion sIi6nId bo cnrricd oiit with ns little i icc~ss to diist ns possiblc, und tliu biisin shoiild LO ti~insferrctl to tho drying oven 11s soon iis possible iiftor cvnporntion is coniplctc.

TI10 following tcrblo gives tlic rcsults of sucli l~larik ospurimcnts with dilrurunt po~v(1ers. Tliu tlcteriniriiitioiis in coli~mris 1. nncl 11. \vcru csccutcd IJV viirioiis iissistiints, iind t~ioso in co~iiniu HI. Iiy students doing tiinnin iiniiIynis for tho first tinic. Tho resultti iirc not selcctcd for iiccuriicg, lint contiiin thc wliolc of tl iu tluterniiniitions oseciitcd a t tliiit tinio nntlcr tliu reslmtivo 1ie:ids. I t w i s suliscqiiently fount1 that 1110 clistillcd \niter was I I O ~ qnito mtisfnctory, lint left i i residuc of 0.0004 griii. aliicli slioiiltl Iin dcdiictctl froin uiicli cleteriiiiniition. Siiiiiliir usporiiiiciits wcru miido with 11 ?uiuililu of Frcilicrg io\vclcr wit11 less Hiitisfiictory rusults, wliicli iii* iioL qiiotcJ. iis 110 dOlibt tliu qiiiility of tlic po\v(ler Iiiis sinco been iiii11rord.

Heeiilrcc /ram 100 C.C. O/ Illutik ILrp-it t ict i ts . - . -_ _ _ _ _ -

,\iiiericiiii poniier. 1 ~icnna powder. 11.

grin. grni. I.

grin.

n.ooos ' 0'0040 '0000 ' .OW! .nono *003(1

.0030 *00?.0 -0OYJ

- I - -- 0-0017 --I 0.0006 , 0.0042 nvcriigu.

.. . -. - . . - . . . -. _ _ . -. - . __ -. -. _ _ 'l'liu iinportcincu of giving iit I O n H t onc iicltlitioiiiil wiisliiiig

nntl syiicuzing aftur tho 1iowlcr is frecd from cliloridcs siifticiontly to iinswor tho iirweributl clirorniitu tesL is sliowri by tho following rosults. I'robiibly if tho iiiiiount of N/lO eilvor nitriitu nllowod \vero retluc~d from 4 to 3

. , 0