I..C.L. 2 L'''A...LO.TL. F'.;.. 3 r r llniI,3. T,' /' T.,: V,~.. J,, f,(3;,...r_ ii.tOVJ!:.?,~iL..t'i;t 3 1 " ]'

PI;:X:::X; of f i;:St $~~

LfJiL0t-T Oki Q'iV)JLCGT 17 RW.~i~i:? 1 GilI dL.G Ot' L: C JOIS T i iI-T, iP'bia, ti' 01;I'T', S,-J -..-i;'{.I.b ~ S * Ak UTh IV1E R6I "Y Oi A. I Cl,I G-i(N Co Lo CLwRJidK.aNiIID A. E. WHIT t'b'sb(.... S,,.CI, A T9t2,Q3 0Jt re p i rt s r 2vts f ks aI tu houre t tests s, the g vex> 0ic.;..S. i....*.... ".o.b..r.., t 1111"SoI t~.-,, $ e.. G.....at each oC thee temdperatutes Co nsldhere( ast:. i:" g ra':: t ( ~. si e,'s p: g froe 241 heat-treatmento 7., the c O.P.Eso..l..f.. i.1

t;he ratio of thre 10 ao ur ru.i;ture strenngth oft th line n.d... C(o Se a 6atsentic grain ed tees wa3 fromi 0 65 to 0 00. T ise s L s ie efor e' erie indi. t e r Jatitn In autS t nziti. gr abin size to ia" e a more mnl o r'a I nfluenT ena on uti.e 1.0 hour riluture stre.ngthi than on the 5:00 hour creep rates. I!n t'ct*, i. tie case of tihe ruitA;ute strength, the range in this rati lo becomes even less when proper consideration given to th,.re ma"x imlura vCar iation in tl e austnlit ic gr in si of tILe st: s bin.g IP Vt 0 0DUCT,9CT0 A reportI was presented before. tie l I-. C Vr;.t:i o'nt'. the ot A.O,. o h T e ef..'cts of r..nu;e~-' " " a,, g i'"' o ethe crp ree $S.S tC E of t eels. Te c2i e f v ar:e It f 4s. e.,.. -., ttuLS studya -W- S tile caustelA'i@ i-' E % ze CZLd, a. t;1Xe b&sS3 OiOB Slour creep tests, it was. foatd th1at fJor e>c o f t he 3 t'kls (, 3v oz —^ sicierea The coarse- grained austeniticl steels pSSgs a lowe.r creep rtetha;t is, a gre~ter creei,? streg n1tlh thavn tdo co-iresepocridcreep r tiv, t 1' 5.j-SB h a g r 0";2, "a'C-,':': ~ sinc fine ograx id steels at thige temi eratarees empos ed a w, A0 ~ White and C.....Claea; ~t this same Conlvesntion at report" wa-s li..ewiu se p-r e(sented,,~i1ch. indica ted that sh1ort-t'ie rpture toruests.offerea a possi:L.1:i i iy o, rap.idly classii'yir.~g sttels.oi. t_,e same te, e ~;i't! rtes.tec' to Jr "~t~,dy o t' Of t Cfects of:i.....r' tee oft;'l" tP 1.~ B. i ) tae's'tOmc e of Str.]-. H.j C Cr oss arna J 3 e iO.- ~ j: F,;,~ f~" ~.LMILcOX91Psa.21.~est is ~f.or ki:ghl Tempera S~ture,,.=.a~Kcte TM $sL tcS, AV E; jWhiBte a4tld C. L. C''l-f.r

tilair relative orcer of creep stnrexgt.a. OXi tule Oasis of tha'.s W"o' x hlowever, too Cefin:. Le cornceilions were riot pe1.1 er dSSiblte as on.. ly.five steels were coniasierect lnd, t frtSheirae, t"-he creep resistance of Bonily three of t Jlase steels va-sas 4..~n In order to obtaifn if',art'.eri in.ormtatl.on witti.res pect ot ti.e relative merits of the shre tl -u rte t,lt -. Iie'vred aCrvisable to szbject to thl.s,;'test cCert-ns of tn,,-'- steels u ~ cc inxt tueb Study of' Vig'.'ar.ia/b -is, tuie xxg 0::J. chat te;s eristi cs oZ: t'etes stee-ls v;Ee alio- i,.ewr; t.;l be deter-mined wSheth er o1r not h st ls... wo.,.b.... areive rela'tiv order ci tliae b'-',si.s oi:' th two tst';,t 1.:i''re.;.'s )nhave )en obfQ.tained4 "y czaine itn i"',i".t Tae steels ased in tidls investigalio were obtai4ned f.rom Lattelle Aeinmorial Institut.e i.. the form r of o.ne inch bars.n.no;.omationL with respect to t. neir cliemicol i yio!osit'on ti,'t'g practice, maelting process ancd iicQuaiJi-Ehn graii size gr e. geon in Tabl.e,. I. Withi oe Otexception, -tL st-els.re.. tk.e, carbon' type, containinxg O* 5 to 03.. iper cent car bon-. ot'<.el,3i lik ewl ise countains 0,!8. per ce.nt vi.taIaUrtM O:

Table I CGemical Composition of Steels Used in icce1tabiiity.ests jesig Ckie-nicaI C0omLjosition, Per Cent h1. ACad:- -.1i-..c.ai f-}tlha;ap t J.an C'L 2 P S 6i V ti onJ Process I (J.n Si ze' t52 0.46 Od54 0.016 0,030 0.;3 oL to 7 5b6 0.51 0*075 0.0,8 0.033 0.21 0.105 J 5 7 393,0.37 0,70 0.. 16 0.18 8 X-20 0,35 0.55 0.016 0.030 0,19 -.. 0.06 basic J,2.L 7C o 8 -.Tie steels were given the sa.ae heat-tre-1;ents a.s e mploy1ed by Ba ttel e and specia _ care ws taken to have all tihe details in str;ict accordaance with thlose 3)reviouslry used in o` d e...c. that tshe resulting grain sizes would be tie sci Po..Ctio.r of each steel was heat-treated to prodiuce a i.ne usteni- -i' g'r i. anid tihis treatrment consistedL ol air coolinrg from eithe:r T-rh. or!1$o00-, Tie rembaining _portion of each steel was ""eat-treated to prodaiv.e a coarse austeniLtic g rain, Thre teperaturees:'sr tt?.S pse ts u.,se "vaozm 1800'to 2000F~ Thile im icrostrueires of Chamrts! to-' 4 skow tLiae lae-ts t -4 2i: 3t C'g4n zi.e for each. of the steeels in both conCl.timos.<t.c-r-eah.. se~t an. tihese s$ame esuls. t e sauriaerizeu In Tab].e I 1f the results of Table II be co.alled wi th.",'._ io'usly reported by AL.attelle very goest agreesa 1-,e ill i e fOund to exi.st. bligilt differelnces are fouont in Heat 3 ign t. 4 tt;;i grui.0 size variations in. thle coarsened steel was p.reviously founld to rl.ng i'roi'l to 5, an&l. in tr e case of t,-20.. tne,:reviotls rlzge was': from 0 to 3

T b..e 1 kusteixitic Grain Size Vit2 Iexi b5btjeted to Des~LcatTe& Trea~l its Steel e1eeat- TreatmVent 52-P1 15509, 45 mrain, Z to 8 852-2 45 mitn, o 4 b56- 15 50, 45 mi. n( t o 4 56b-2 t lkj 850, m45 n. 2 to 4 13-) 16100, 1 hro S 333-2 S000., 1 hr. 3 to 5 0i-3 ()O 1550, 45 min 8 i-0(2) 1900, 2 hr. & 6 hr 1 to Dessrilo Sio o e......... " I tttt j. cou osists of fr&ttring a ses 03 S- rir- e-r Vt'C -. re u.esr ixed loads so it ost t that txr e ttt:Lu It;,'" QSe.. -Ct.' trres Vary from a i'ew itmutes up to a uax —rnum t ~5,ht~.:.s,, stresses arni corresponringfg fracture tImes -,1,e wa olo.te. to la.yo r, Fa r rS I; t S C 2 f> 4 X a1;e S9 C 3 2LI1 1 s JSE S;i.m t iy tr if; _.e re. A.4 aritmanic coordinates> ~oZr'~'l anpjproximately s'traigit-line re!~ tionshnip at.each of the tempera.tures. It is ts p os.'osib~l to deteeraiine tihe stress corresponlcig to a aefnit.te fractu re trime, such as 10 hours. In t'e present inxvestigatifon, specimnexls: af eash of thle.our.1 steels were giv'en bothI of tihe heat-treatmenyts ligsted in al',-.

II. In ehach ca se the secimens ieat-treated at th le lower t perature possessed a fine aLst-enrtic grain size sd those teattreteQa at taie hi'igher temperature )ossesse a coatrse i4stenitic grain size. Thre results obta.inea will, therefore. 1dic. te h;e influence ofi austenitic grain size on the ruptu.re strength MiTe results obtained from stress-r.riture te of ao maximaaum of 15 haurs du.ratton on these four steels 2 Sre S"or-w gy r?.o' iclly i, n ilguraeJ s 1'to 4, Inclusive, ara iikewise given in T.bles Thie four f-i t;,: C_ Swicbh are. lofted'to tIoga ci.t.u......ox'ainut-res, celarly show'i e coarse gra-iedm stnii s tes'to pocssess th e g reter r upture strength at each oft:hfne.ei e rb,,, tu.es, s:)ic telv e,, Tahe inferee La sitr e.h bt ween tWl. c ri;e oiarsad fine aELsteni tic gra. ed ste els apeas to be el vl cntt for Steels b, 3 a bb and $i3 an.d of a greater orcar o for rteel K-20 o Tables i II through VI contain, in hd"it.~i. -to L:.e stresse anua correspozncting fracture ti;rrmes, in!L'ormr'aat4'iozn wih t respgct to 0the o:uctility of tee fract-ured specimensa. iAven though ti-e testing tinme periods in t'iese tests are relatively 7Snort, th.e a Ltility values do 4pgivqre L;m ind ication;4 of' thte 2influlence of time. nd. stress o' bothE

tie elongation and. reducation of. area. W-ith all the steels thlie U Cctility of txie coarse &a.stenizic grakin steels is less t.'r- n s. that of thle fine-..trained steels. inof tie case of Steel 52, the aiferernce is not of a largc. order of Laagnitude and botha gr;in sizes would be said to possess ample aucltility. With the reumaining tin ee steels, nhowever, tile ductility of the f'ine-raiinedo. s tu ckte is am.ple but that of tLie coarse-grainlfed is ]. lOw, th1..e eCIongal tioon being b'elow 20.per cen, LspeciLally is thLis true wih Sth &. 9 36 at 6850FO an.8 te el i-20 at 850 T', Ta3ble VII sum'aLarizes the results from boxth t.e ub O -',) i cr-eep tes ts and tile stress-riopture tests, Wrile OJ.'1,.e -,iI si ov-s thls comparative'iftn3u.ene c' o af stenitic grai.:1 slze t:.m c7,i'n.;' c"' p aeckl s'aoit-.ti'i. rIu.tirtlre X strenlzg t. h. Is tis table tVe c.n.i. ison in the creep strength is ad.e on tie rati o of c rp re ta'es an. in:tile stress-rupture strength, ou tnhe ratio oz tile 8$r LPesses reqj2.ire~a for fracature in 10 hoers,. The values of' Table VIII shlow tle ratio ofL- the creep as some sower of t.Le stress and lievwise becuse certa-i 3S -ofle bOO hour creep tests entered thle thirs stage while ottll.eors r'e!t. ied~ in tXie second stige,. In other woruTs, certain of" tilVe, s of pi.re thnira stage cree'p srates with tsecomn s t&e- creep rates...t'nagSe swoumld, have belen consi's e rably less if' thie stresses'Lh'd ci'eso chosen tlhat all the specimens remainedt in the. S t'c t h 11"I t~~~~~~ile se —con-d s~~~~:,COD CI.-IIigc ~a a.:~'

In the c-ase o1 the rupture strength, th Q range in the at o is onl f'ro; 0o65 xto. 0:30J0 FoO. tlernor e, th'is o'bserved falsge in the ra tio is directly proportional to the di'ff,~rence bwetwee n ti:ie extremes of tie austenitic grain Size co, s-i eia. i'or exmpriple, in 5teels 5: anrd 56 the Line x.ustenitic iGin szize ad a ratinig o to 6 to 8 &nd the coarse a rasting.of: to. or i,. -rverage difference of. 4 grain size numerals. i'or b-oth. o' t he 2ss steels tae range in the r.tico was ontl from 0,84 to 0.t0 -io r Steel i-20, an averg.e.ifference of 6 grain size nue.rals e.:i< A.sd C'n2 the average rat.io was lower, belng ajpproximat Lly 0 67 In oth.er iwoiros, as should be expecteas thLe sl..ol4t;y oo t.l.e ocarse grain stru. ctuare over th'e fine grain steel inc'ktscs as he rel'ative s'oread. between the gPain sizes considered n Tlercm, DIGIC.U-U 01;' RL.WILT$ On the basJs of these results it is to b' councluded. that both tue 500 hours creep ts ts n. the L our.tesu s t rss.....tr 1hu te:,sts sihow the coarse grained austenitic steels to. poe the superior hi ghl temperature strength at the temperat. u r e s caO s: e eOU, The stress- ru)ture test, however, slhows ttie.ln'i"ue:,.:'ne c oini',.,hc. gr..in s:ize effect to be c0onstant inM all four steels aEiC. t, ch of tile temperatures considerea. C)n the other i(and, t he creep bes'ts do not show a cons-istnt tn tegree of imprrovement in tae high tem:[)era tu.re strength with incrl easinfg g~ar~n sizso

Thle stress-e- aptare test liilaeWise shows t it even talough increased high tempderature strengtl results froml a coarse austenitic grain, lfull acvan1tage cuan ot lWay;s be taken of this f4ct becauase of the low high temprerature U ctility vwhich. recsults in certain of t'he steels considered.

Table III 8tress-ft'up'tre Data for -Steel 54 _'ii~~~~~~~~~~ fC~aed. t iorr et T Jemperature es s Tie r s Ti"-e 1 OgCtln.. rtiea __f-~ 2_ ~' 5_ ari-. L bu i(Hrs i —, 2 T,' e2-1 950 0, 250 S Tv T:" 4"" "SO9 40 5 000 0083 41,5 80 3 950 40 000 0.60 43,0 77 0 50 3,500 14 4o 0 7 6:;50b 2 9,000 04O,~b. 74, S. 850 63,000 S.TQT.S, TO, t5 7'J'.3 850 58,000 0.083' 40.5 78. 850 49, 000 (88 40 5. * i.. 0 00'. 41 $! 50 7:' 2-,2 j150 51,500.T i 9 u.0 950 41 000 0.3 37 5 6 -3 50- 350003 4 5 3.;,0'' 0 950 3, 000 11.7 35,0 6c5 850 67,500 b*T T,$S 3b'0 8, 4 850 58, 000 0 50 32 0.' 8 850 50,000 4 027 30.0 5 850 47 000 14.2' ~8.5 5. 5 2 -! 1550'F. %5 rain. air. cool 6 to 3.,1800%', 5.i lain.,O air cool t2 to 4)

T abl.j e IV S t res —uxture ta for j5teel,5.'au' ti on Heat Teompeerature S treS s Ti ae'H clgztion of' o ea N.x ber beg.tr. 1b- In.ou^ rh in I Tn.. 56-1 b50 5 000 S.'.T T. S o0 o0 0 80.9 9bo 46, 000 0.38 402Q 77,8 50 a41.o000 1,45 41,0 7445 b3O) v 33,000 12.52 e.5 68. 2 8, 50 3I,250 b To T.5 $3.2C 850 60 ~ 000 0 o 37S;70 780o 8 50 OOOQ 00037 a 38 850 55, o000.70 10. 0 7. O 850 )b0,000 0 7 8' 73,'S 56-2 950 62 00 OO0, "'. T.. " -ai e 350 5,.00 0.2: " 5 b 0 _44,.0000 4,13 5 "D 350 O,000 10 647 F:' 5 850 77, 000 TS. To8 T.: 7 C 850 68 000 0037 0 54 7 850 65, 0000 ib 503;. t 0 z2 5 850 62,000'5. 03'0 ~ O...,. 850 60,000 4.32 2'0.5 850 53, 000 16.5 1.9' 41.6;l: 1850%3,', o45 rain:, air cool 62 to 4)

Table V Stress-t.upture DataE for Steel S39)S A:-at Temperature Stress.. a.gat S1.o 1r e ~1 1 cinbe DgP. Fjtaoq Ju,iiasr, 393-1 850 68, 15 SE, T ~,T*T. b50 850 63,000 0 13 36 5, 9 850 58,000.52. F0 850 56, 500 8.12 1,59 5'7;993-.~ 850 90, 000 80T,T.$ 3.9 0 4!: 850 83,000 0,28 17.0 30 2 850 79000 1 48 12 0 19 C9 850 76, 000 2 45 i! a 0. 1 850 70,000 ll 77 7.5 i 5,3931-!: 16000F., 1 Pr. air cool D),o 33" -' 2-"30"F x ~ i ira, ai r cool $ toa 5)

Table'VI Stress-Rupture Data for Steel K-20 Reduc tion?Ceat Temperature Stress Time Elongation of Area ~umber. D_ 4 Fahr, Lb in 2. i-20 (1) 850 45,000 S.T TS 52. 5 79.5 850 40,000 0.40 56.0 79;5 850 36,000 1,67 56.0 79.5 850 32,500 8.30 57*5 79.22 850 31,000 =k2 580 4 7 50 55, 500 S. T T. S. 49.0 76.8 750 514.,00 048 49,5 74.,5 750 49 000 l 22 52,5 75. 6 750 45,000 6.33 52 753, 750 43,000 10. 3 55.5 78.9 750 42, 000 21. 60 555 76..s KS.e (2) 850. 62,750 8.TaT.S, 277 3 56,0 850 55,000 0.90 22, 0 38 850 53,9000 1o80 -20.0 34.7 850 50,000 5.68 15.5 30.2 7 50 76, 400 S.OT. T.. 29.5 58,8 750 69, v000 0.95 26.0 49.b 750 67, 000 2.19 24J5 48.9 750C~' 2000..,. 750 65,000 7. 22 05 40 4 - 0 1 I). 1550oF., air cooled (8).:20 (2)2 1900OF., 2 Hr., air cooled 1900F 6F. 6 HIr, a.-: oooled (l1

Creep and Shlort-Time Stress-RuiptuAre C'saracteristics of Designated Steels Steel Temperature Stress Creep Rate Stress for Fracture Designation Deg. Fhr, Lb., %/Hr._ in 10 Hours 52-1 950! l,000 0.0120 29,000 850 20, 0 O00910 43,000 52-2 950 11,000 0.00066 32,500 850 20,000 0.00048 48,000 56-1 950 11,000 0000313 34,000 850 20,000 0.00415 49, 500 56-2 950 1,000 0.00038 40,000 850 20.000 0.00019 59,000 393.4 850 C5, 00 0.000135 56,000 393-2 850 15, 00 0.000056 70,000 -20 (1) 850 7, 500 0.000120 31,800 750 28,000 0.00426 43,800 K-20 (2) 350 7, 500 0. 00021 48 800 750 0;8,00 0.00009 64,000 52-1* 1550-F., 45 mino, air.o 1; v 8.. 52-2' 18000F, 45;nin ~ ai r c.x:I-'; ~.., o9o-1. 1600R. 1 Hir., air c o393-2: 20000b. I Hr., ai r co0-"'':O -' K-20( ): 1550~F.., air cooled (8 1 K-20 2: 19000F., 2 IL - r.lo o:.o " r-0, I, 6 Hf. air cooled (1 to 3)

Table ViII Comparative Influence of Aust:ientic Graivn ESize o(nV the Creep and Short-Time Stress-Rfupture Characteristics CrRee. ate* (F.G.) Fracture Str ess-o ratureF~~~L~R~~;c~; a_____ e Cyt. Fractux Strelean ss (nC G 52 950 1.8s18 0.0 89 52 850 18.95 O.090 56 950 8, 24 0. 85 5r S b 850 2 8:1 O. 84: ~I-20 8 50 5.71 0'' 700 50 49,r. 6 XResults based on Battelbles Creep SB tesso'.9-Ctomparison. based on str'ess requir. ed for fr:1i:u. i.0 hokrs,

KE1FF2 & F S -n. ER N Y. % ) - 1 _ _ _ _ _ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~. r_ _ -+ -. X 1 _ _ _ _ _ _ _ _ ___ i - _ _ _ _ _ _ 7G-t |__ __ __ t, _t Chara terilsti Ast 85D 5OYFtvK] 6C { t ~~Ig ____.1 I If 4 f-tt — i — 5Ut —--— r-t —--- i —: —-: ~1_<0 H ----- -W= ____ _-_-_ t_4~~~~~~ T ~__ __ f 1 1 I I __, I -' L1 23 i _____ 4 iJ~-$ —4-| I [.-.- ___ __ - T6- - _ _ _ _ _ _ _ _ _ t jI; - -lii-z-; - - - - 1 - 1 4 1 l 1 ___-____ __ 1 L L 1'_ _ ___ -—' l ___ ______ l l i l l |1l ____ 1___ 1____ fotrcitr1us 1 -i l l lll L t7I ll 1 1 -_i 1li1 _ _ _ _._ _ I 1 1' jIIIIj I I' I i 1 1L1 1 1 - I'_ _I_ _ 8 2, 4 5 6 7 t7t891? -t 3t _ _ | _ __ _ 1 78 9 * 5 6 78'9-L 2 3 4 5 67 823

K E F F:,i't:l:) ) i,,,,, Q. *. ~ ~ ~ I ai IC = =Xv~~~~~~~~~~~~~~~~~~~~~es'Rpu Iirceritc i 5OF 7ytt' -- - ~~~~~. —- bF!F-Rt ctal~~~te eIQ a. 15 tn — -+ 6t +^tX ~~~~~~ ~~~ —-t —-- A-t-+, t,1 t j 0 __ i i i t I I I I - + —— tW -— 0 { —4~~~~~~~~~~~~~~-t 5 5 - - - 0 —t 1 —tt-;_l F_ 1| 1+ +* i-,I- T - -- -- t —+ z [-[ i I - 1: 0 1 1 1 1 0 f 1 1 [: > e 1 1 1 1 -i 0 I~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~........ 0 — l --- 4'~g4- ~T]i:: — X tiI 4 — W<1-1 - 7 - 1 1' # 1 1 l l l 1 1 1 - 0 f:- -' ~2 =0=3' | | | [: i I 1 1 1 W~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~...... }~~~~~~~~62 1 | OF:4| i jl t r f0- 0 170 8 3t 4 5 6 7 8 9i 3 4! 5 6 7 8lo

_' t,;, t'' ~, I i - _i_ - j. T r. ___r-I- If _ _- 1...,, b, * s * - +,i............. J —-. 4 [4- -- -r-l -T4 t * J.- *-*__ _, _ _i_ _ —- - - -w — +- -t- - -t t- - - - +- -— t —-'tt —-1 -i' —----- - 4. j. i _.. i ~~~~______ ---—' —-------- 1- - t ----- -' —;-_- - k — t- -t —---- ---., i' I' j I<'tye$s llXpt-ure:C:largcteri~tics iat 550YF; ~ i 1, J (e —t,~~~~~~~~~~~~~~~_ ___ ___ - ___ _ -I —f-+- -_ _ _ ____-t ___ ------ -t —- O —+-t t- t -t!.....,,...'.. tb r~ -o., t' t ~, - 1- I --' I 9 -; - - -,.1 ti ----— t —- —— t —-------- -----— t —- -— t —— t + --- ---- 4 Ij I — r —t 4t:t:: t, i... t'.... -...... ---... —-—.. i...- —'- t.... f i_ t......... t.........:.....'.... _....I — j j I 1 1-. —4 4,,. l!, t t 1 1 1fiI X I.~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~'t-'t~t' —~ —-- -t — --- 4 --— +-+ —-+ —- t —--— ___ t... ~... I ~. I. i ~:...I..' I I I I I III I {~~~,, i,,,; l,,; i,!: t, | 1, _, 1.... 01 tt!-........ -....... - t-....,.... -1- - -- t.-.... r __ i! t. ~ t t | - t I I I I'. 4 ~ ~,............. t.....;...... t.... r J' ~ i i ~ t I -: I: i 1; 1- l 1 1 }~~~~~~~. t j,....,,, 1 ~1! I I. i t I' I, -';1 t I,, I f i t! t "'!! -, - I t — ____i i -:: _ i --; _ ____ t...........'., I ~ I, I I I J I I I ~ I lo I'~ I. I,:I....!. I I tl ____ __ 6 _ 4 5 6 7 I P + ~. ~., ___'_-___.....- - -'~' " - ~'-' i~:~'-"''' - t..T l.., - -. I I. -ii i - -I 7i't'v_ tiG~ ~~ ~ ~~~~~~~_ -t —.- - ---- —!F —- — w|,|i i~i |t.... t. --- --- -4 —4 —- -----------— t ---,: + -.+- -. ______ _-__ r -_ 4sp., ______ _. _ - ---' I, I I I +I I _I _ I... -t,I 0s1 1'4_L-;+ -1 =<L —- ftt, t ~ I, i I i tt 4.11j j /! j jj:. j —-................................ 1 -- - ---.- L 1-, i.j. i.. 4.....................!... j. p... t, 4 — -] t t! ~ ~l I ~: r,., —- ~ + _ i- -----, —:.i l,' { t,!: I ti /'''' ~! L?~i J-w x~+W> "t ic i8 I-' - i'-+L -''.... I ~ o is->.oq~. i;,(o, lrco ttn, a,1i, * ~., j. i i,,'; I i t I / I, I I -I I t>)' "!' i' j,' j X T mP.or.~ir'ct:re, Houirs, I: { I I,''' L: _ ~!.. I - 2] ~ i_ i ~ 5X 6 i'..J 4 _ _ _ _ _ 3 * /:f 8 9 $ Z ~ ~~~~~~~ 3; 5 7:. lS'' 4 5 6 738 V 2 3 4

KUf F EL &' S -R CO.. 9-! -- -+ —-c- I I~~-F —-r ~ —---..Srs-.. Characteristic-. at,, i 7;1 1 i I _ _ _-~ e e.......... 670 1- - _ < w | - 1 I f I- I A - f t L —f - l 5' —t i-4- J —-= t,' —1 10 tN- I-tt Ia41 -<4 ji JL 4JI t-+ tt- 4D1: _!- 1tt - iT t tt n. AWLf o n ]i | I I - ~ I i I 1 1 | I 1 I I. f I i,In h 0, L..........: t| 4.n 5.1 - i —— ~ - i - 2<>i -i l e d - i'' i 2...... 2. n ~~~~~~~~~~~~~~~~~~~~~~~~~~~.7.0..rs....... 17 8 9' -7 8 9 3 4 5 7 "i2 -3 4 6 8

UNIVERSITY OF MICHIGAN 3 901 5 02827 2865111111111 39015 02827 2865