Document 6RGb8dyN32XmBrRzaw5Jnnqpg

PRODUCED BY FORD f. ;r S3 O r O O a w a> WAs' 'jy 'W :!'ll! I r . ! ;::! M:ii !!;!;!> v :'i :.!i; i'Hi 1<M! * i* ! :tj:| .:iij| 11 "ii-:: ;.i;'; :ii!l "in -4 M i ij-lii!. Jm ! -y>* '; '.y v* '. ''r.' r* *, * '.*."*** . " rv... *.*. waaiiiatimtmtim 190 o. W. **ini.*v A*n U. UAVAWV ns fttwrati**!, eitb a mHrrw wifru'Mi #*Srr rKflum, Hn*' *wl H# f4, maintain rlrctrieal neutrality. Bat! and Taylor (1903) Have given a detailed description of tb* before, geneou* proteef by wbieb the dehydroxyfation ant rectyitalfixation of *etpeutiue (both ehrysotite and ptaty form*) may ub pl*e*. TSey oouaidetrri tbe formation of foraterite and at*o, at higher fomperatum, of Mitatitf, and, under hydrothermal condition*, of tab. Although tb# eryatallograpbio rotation* provide strong pointer* of Vow tbn* 'ordered* reaction* mar occur, they acaredy fire quantifotiro faformtion. Since tS* reaction* probably oocor on a fine acale, poaiUy vtthto domain* of tbo order of ilH cm in rite, it not a*y to obtain any direct information on tbo ionic (mainly eationie) migration* by wbieb they are onridered to taka place. Tbe preaeot writer* bare ought further information by making quantitative measurement* on tbo development of font*rite and, *a will be *hown bere, tbe remit* augguat a *ome*bat different eeqoeno* of event* than tbo** postulated by Balt and Taylor. Rxferimmtol A naasira terpentine from Quebec Province, of line grain rite and pat* buff colour, wa* need. No mineral impurities ore detected by X-ray diffraetioo. Tbe mineral appear* to b* a layered ftructere with eooriderabW atackmg disorder. Po*dera with partiel* *iie* in tbo range < 90, > lOO-meeb acreen eice were Heated in air m ueeompacted form on a tbermobolance at 570* C for period* of about 50 bourn. From tbe . lee* of weight compared with tbe maximum lorn at higher temperature*, it era* determined that tbe mineral vu about 90 % debydroxylated by thk treatment. X-ray diffraction data showed no rceidea! reffection* fron unreueted eerpentino and no detectable for*terit*. 8uboequent beat-treatment* were carnet! out in air in temperature-controlled furiiirr* at temperature* ranging from 55(7* to 900* C for period* ip to ICO boon. A few experiment* were earned out at Higher temperature* up to l WO* C to etody the formation of enatatite. Foraterite w* determine*! quantitatively by integrated X-ray dif fraction measurement* using borhmite a* an intern*! standard. Four forvteiit* reflection* and two boebmite reflection* *era measured with a aeanning speed of |* 2f/min. Tbo results are shown in fig. ( where the amount of foraterite formed k exprwaed as a percentage of the weight of tbo final fired material, l.e., aa a percentage of completely anhydrous material. The maximum T*Au*m>UATmw nr axaexrrim 151 mount of fwrvtrriti* lnrnljwl k *fmt U? **m sT tbo might Ik fufiy aabydromr material am! b obtained after beating at C C for ponol* ef 90 boure or longer. Tbo mtema! standard, boebmite, w*a calibrated witb'feepect to a nearly pure, wafl-cryatallbed, 1 fused<caat* feruterit*. Tb* latter oemtained Just detectable amount* of 9fgO and climvmstatitr, eatemated at 5 to T % total Impurity. Determination* mad* without agowane* for tbe** impuntk* may be over-e*timatad by a few percent. Fib, 1. Wt|M percent of forctedte fcred bow pe*d*d wrpeettm la por1di *p So lQpkpmvtii t**l*tf hoCAerwsffy el frapnltm *fcora I* "C. o that tbe value of 90 % for*tent* may oeed to b* reduced to about 75 to 79 %. It wa* ob*erred that tb* reffectioa* from tb* forrterite derived from arpootia* were broadened vitb ropect to tbose from tb* High-tempera ture-produced forsterit*. Tb* broadening was approximately tb* satno tmapectiv* of tbe time (1 to 99 bourn) or temperature (W0 to 900* C) of tbe beat-treatment If tbia broadeeing k attributed to *ma!t cryitat etc*, and if a oorreetiou for Instrumental broadening k baaed on tb* redaction* from tb* bigb-temperature-prodored foraterite, then * value of tbe order of t x 10~* cm b obtained for tb* rryata! rite of the foraterite obtained from terpentine.1 If tbe broadening ariar* partly from lattice 1 TW conw Hen --it for MwswiUl Wowkwtwf to t 7k cry*W *1** I* caVvlstcd ka tb* StWrrcr knU: t Af I ,*! ' it, t V -... s * ..' ' KK r*> Vo