CIHM Microfiche Series (Monographs) ICMH Collection de microfiches (monographies) Canadian Institute for Historical Microreproductions / Institut canadien de r. roreproductions historiques I Technical and Bibliographic Notes ' \otes techniques et bibliographiques The Institute has attempted to obtain the best original copy available for filming. 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This item is filmed at the reduction ratio checked below / Ce document est fifmp n;; tsux de reductlori Indl-ue c\-d-\ 10x 14x 18x 22x 26x 30x 12x 16x 20x 24x 28x 32x The copy filmed here has been reproduced thanks to the generosity of Ecolc polytcchnique, Universite de Montreal, Bibl iotheque The images appearing here are the best quality possible considering the condition and legibility of the original copy and in keeping with the filming contract specifications. Originai copies in printed paper covers are filmed beginning with the front cover and ending on the last page with a printed or illustrated impres- sion, or the back cover when appropriate. All other original copies are filmed beginning on the first page with a printed or illustrated impres- sion, and ending on the last page with a printed or illustrated impression. The last recorded frame on each microfiche shall contain the symbol m (meaning "CON- Tl^ JED"), or the symbol V (meaning "END"), w.^ichaver applies. Maps, plates, charts, etc.. may be filmed at different reduction ratios. Those too large to be entirely included in one exposure are filmed beginning in the upper left hand corner, left to right and top to bottom, as many frames as required. The following diagrams illustrate the method: L'exemplaire filmi fut 'eproduit grace A la g6ndrosit6 de: Ecole polytcchnique, Universite de Montreal, Bibl iotheque Lea images suivantes ont 6t6 reproduites avec le plus grand soin. compte tenu de la condition et de la nenet* de I'exemplaire film*, et en conformity avec les conditions du contrat de filmage. Les exemplaires originaux dont la couverture en papier est imprim^e sont film6s en commencant par le premier plat et en terminant soit par la dernidre page qui comporte une empreinxe d'impression ou d'illustration, soit par la second plat, selon le cas. Tous les autres exemplaires originaux sont filmis en commencant par la premiire page qui comporte une empreinte d'impression ou d'illustration et en terminant par la derniAre page qui comporte une telle empreinte. Un des symboles suivants apparaitra sur la derniAre image de chaque microfiche, selon le cas: le symbole — ^ signifie "A SUIVRE", le symbole V signifie "FIN". Les cartes, planches, tableaux, etc., peuvent etre filmAs A des taux de reduction diffirents. Lorsque le document est trop grand pour etre reproduit en un seul clich6, il est film6 i partir de Tangle supirieur gauche, de gauche i droite. et de haut en bas, en prenant le nombre d'images n^cessaire. Les diagrammes suivants illustrent la mdthode. 1 2 3 MICROCOPY RESOLUTION TEST CHART ANSI nnn ibO TEST CHABI No 2 1.0 128 1,1 I.I |40 IIJZ5 [12.2 IZO 1.8 nil I r\i '•4 mil 1.6 ^ ,-1PPLIED I^VIGE Pl^BLICATIONS •C, 111- nil, ^ ^'^>'''^^ DOMiNiox ohsp:r\atory * '^ OriAWA. CANADA Vul. IV, No. i y v^ ORBIT OF THK SI'K(TH()S(01>I( ' B1.\A1{V XAIHKI.K AM) A NdTr: ON ij iackut i; Bv ItKY.NOI.lJ K. V()r.\(i, I'll D. Tlic l)iii!uy (•liai..clcr ol" X AuriuM' (a = ,")'' L>(i"', 5-+;V.'° 7', ukiu. 4 SS, tyf)c BI) was announcod l)y I'lost iiiul Adam- in the Aslrophi/tiicit Jonnud in IlMW. An orbit lias been iletcrinineil from ciglity-eifrbt >inj?le-|>ristii siurlrogranis secured at this observatory during the years l!»i;j, I!tl4, 1915, and 191(1. An idea of the .speetnini may be olitained from Table I, whieh gives the wave-lengths of the lines used in niaking the reductions, the number ngtlis by the usual method of n. iking the weighted mean of the residuals etpial fo zero. The residuals (pioted are taken in the sense, observed minus the mean of the plate. In addition to the lines given in this table, the // and A' lines of calcium an; present and generally were measured, but they were not included with the rest of the lines for n-.asons which will appear later. On well-exjiosed plates all of the hues give;, are fairly sluirp. Those due to silicon and some of those due to lielium are faint, which accounts for the small number of times they were measured. The velocities obtained at the Yerkes and Ottawa observatories follow in Tables 11 and III, 'rii(> headings of the columns in these tables are Mf-e\planatory. The resi.iuals. as given under OC. were obtained graphically from the final curve, and so may occa--i(mally be a tenth of a kilometre or so in error. . TABLE I \i iiiriljcr I'.li ■innit \\ a\c-I,cnf;tl] Aritliliirtir- .\lK'4ir.iii' ■n,t,,! of Timo^ Ur-,>ii(lu;il 1 11' si(lii:il WrlKl.t .Mea-iiirnl IlcliUIll .•{064-S7.5 1 7-.5 + 2-1 t 10} .32 llcliiini UHm-lIT (> ■ s + 2-1 s ■i.-j llcliiini l(L'Ci-3.",-J .■)-7 -!- 2 i'.'.l'. 79 llydriigi'n. . UOIS'tO ,']-S -00 ;!0> ♦ti Helium 4121 (U() S-3 -0(1 .")S 19 29 24 61 40 Silicon 412S L'll 10 (1 -:i-2 f) D Silicon Helium 4Kil U47 114:5 'J2S 'i-2 -.'51 7J 225 1.3 J ( arbon 4.'(i7-.'!(U 7 1 --2-S lydrogen tlMIMWl t>-7 -.'JO 4Si 8.3 70 Iclium 4:iSS 10(1 -\\i r.hi Ipliiim . .-, ,■-,■ MT 403 P04-01 .lagnrsiutn .. , 14S1 1(10 .-.■7 -1-2 ;i4 72 54002- 1 /v ^^ [COLE POL VTECHfllUUE B!P1 lOlHtij'JL IM HI.K AllllNS ()!• IIIK DOMINION Oll^KUS A KtUV TAltl.i; 11 MliKKS (>ltSl.l!\ ATIONS ol X Allili;.!'. Dulc ,lulmi\ l);iy \i'liirlt\ ()-(' lOOl! Oct It) Orl If. 2.4iti,:ir>;i s'J.'i •I'.IS ■ 7h-' 101 si I +■24 2 f-in s f 12 H -24 - 12 lAHl.l. Ill OTTAWA OISSKIIVATIONS OK Y Atl!ll'..K Plate .JTOH 5804 5H18 5S34 :iK49 5S7:i .'iR04 .i022 ■|!V2n Wt." •.(•7:i t'i:!'.i7 ti4r.(i r,470 f.4s:i r.48ii ti4Hft (i,"l()S ti.i2('> tir)('i2 ti.iX7 (■.,59:5 tiriOit liti<)4 C.fi 17 itt'J7 6ti;i9 'I ^ 1" "i <: ^ r v \ \ i-V' \ (• II II ^ II (• i>, V II CI" I'' .Ian. .Inn. K.-h l\l. I-ch I'oh Mr,r S,.pt Oct, ( U-t I )(t , Oct. Oct. Oct Oct. Nuv Nov n.c Dec Dec Dec Doc 1 •21 (1 11 !.•. II 17 1 II 2(1 i DHtC .Iiiliiui Day I'.IIH Nmv. 4 2,42(),07t> (tl.') Nov ■| 1177 .S72 N.,v. t'l (I7H-7I9 Dec .s 1 Ml 774 Dec. IS i2(Mi2s Dec. ■ >■> I'.tU 124 7.S() i:i4 72«• 1 S7 CilM 2():t ■ .■)7() :{iw-.ss9 407 s:i9 4(i.Hs:i;{ 410 .s22 412 911 417S87 42li-79l 42S.911 4.-.t-.S24 4li.')-74S 471-7.')7 472 w.W 47:M127 47S ■ 7:i:i 4S3 ■ 7.')7 -14 11 -14 r. -I.j 2 f I-.-. - 2 .". + tl-7 - .s 4 t 7(1 f 17H -r29 1 l-ISII + 22-2 r21 ■ 1 f 19 11 ^24-7 + 17S +- .V2 + 20 S ^lli-4 + i:i:i ^10 7 -i- !4 i'. + 1.V8 - 5 9 -9-7 + €.7 r 20 f 9-9 - 7 7 -10 2 - 3 + 113 + 01 + 4 3 + 3-3 + i-:{ + 71 + 12 -12-."> + .VS + 1-4 - If. - 3-7 -L. I\.t\ +- 2 + 2-7 + 1-S + i;i - fiO + .H-9 + 1.V2 + 12S + 10-9 + 11 + 13(> + 9^9 + ;i-2 + 12-3 + 17 .-. + 7a + 10 .", - 37 - 01 I tLULL rULntunuit'UL bibli'JiHFl'llF (lumi III iiiK >i'Ki rni>s( iii'ii niN\in \ Mim.i'. 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I -7 I ; II.-. I III :i.-, ;iii Js lis II 2 J II .'«. .■.||7.1 \ . I W 1 JJ li . 1,1 I. J I .'. . I'l .1 . II. .'. ■ :i.l 7 1 I.-. ■.' 1 s ■J'.t .'.I I". I) Js 1 .J L.l'lT \ , 1 W I .l.'i I) \ li f. 1 .VD 1 :i.; II 1 27 II S JO 1 i J J .1 I J I !l I •J I 111 r J'. I J J ■ O 11 O J.N 7 (1 II Midiii "I 111! -"''•" " tn>. ulM. HIS >!(■* X M 111'. K M KAMI HI > "I X \1 lt|l . 1 Innlift'iril :i!i.t.l '-■■' ;vHii >>?■' ■.\'.D\s r.j". 4(X>"' I IT tO.'li I'l- 4101 '»'•<• 4lii nil'. 4i.;s Jii 4i;u lit: 4ii:i '•-'^ y:ui I'M 4., Ill i.il 4:iSK I'KI 44T1 I'T'i 44H1 4tl«l W.ikI'I"' I iirv |{:i.li:>l Vciiii'iiy // nil. I K I'll'.!) \,1 W' I'l I 1 22 ^ 1^ I 2\ \ I > -' 1 - 2 .". 1 7 4 - Ill :>.! -I- 'JH 1^ f n u - (I ■J^ IT I. .1711 V. I \Vl \ ■ 1 \\ ' III .' II 'I II II 1 J ♦- 1 ■-•> + -js i;."i ^ (t u - JS + JO I r l.-.J \.| W 17 ". ; II II I hi I. : HI :. ' I'l 1 i . :i 7 1 ,'i II ', - (I JS + 3.41 1 -•>-2.:tl ', 1 II ; ii. 'I :. I I. ', 1. J I 'I 'I ', ■ i sj jii :i'i II 07 (I JS IS II IJ ■". II. 'I ; 7 1 I J i ."> IIS Jii i;i II IHI JS . Jl 1 . n II \ , ! u . V.I \\ ' r. 1 I i I Hi .'. ; 17 I. \ I 7 \ 1 s II ■. III I .1 s 1 IJ S '; I J i - .-, (II f J4 I'.l ) II II - (I JH ri.iiiii \ . 1 w I Jii^i » I • 1 T I , :! s I "1 k r U .1 1 f "• I) ) . T 1 i '.I II I T (I S .711 r 1 .".'.' + j:i 7.0 - 14 - (I JH i 24 7 4- i:( (1 I'l HI,lr\ I |ci\s OK llIK DOMINION oBSKUV \ I ol{ V NirvSllilvS o|' \ \n!lC,,K Cnni,,,:,,.! f.r.i; \\i V.l.i.iiv l-7s II 01 (I L's 1(1 10 \.l \\l s S 1 _ 7 . •> \ S J ', • .■> ■ .S \ ',1 '.1 \ r .". .s ' "J-ti '. -i-!:!-r I i; .'i 1, • :!i-7 i 111 1 • 10 '. • :il ; 10 -J i r- liN ', I'.l !' '. • 10 ,-, ', S 7 1 • 1 1 J ', ti;; ; • 1 1 i i."p i:i IJ II 12 0-2S 14 r. ;i-7 OKBIT OF llIK SI'KCTKOISCOI'IC BINAKY X M ItKi-K Ku.liiil Wldcity Mi;.\Sl Ul'S Ol X AlltU'i.K ( iiHtihUiil iif.:{'.» Vcl. I \Vl :! t2:i4 + i:i .-. i-171 +'.'ti-() + lS-7^ + 2-(V 17 2;t 0<«> 015 0-28 + l.VS - 01 li()13 Vcl. 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Wcl«lllr.l \„ \d ( 'urv. -r 21 115 - 2S :!7 - OK) - 2S r l> - 2r, - - ;;s :,'.\ 22 2s \ () r 4-2S - 21 04 - 0-2H - 2S - 11-72 + HI -11) + ()-27 - 0-2S - ls-27 -T 2:!-.s2 - 0-2.') - 0-2S Hi 12 ^ 27 ^S " (1 ■ 2:i - 2S - is 7 - .-.o + 2\ - 1) - 00 17 hi 2s li Ka.ii.il \ Clorif y // ai-..l l< _ IS - ti - 17:i IS'I) - 21 s - 21-.-) - 21 ,->J002-2j 12 I'lm.K ATlONS OF THK DOMINION OUSERVATORY MlOASlKliS OF X AL"RK;,E-r«H/inu«i X -•l-ll 7L'r,i 71.'S0 7,;i(i j 7:{'2:i 7:i4,5 7364 V.l. Wi \.l \\i \ . 1 W 1 \.l. \Vl V,l. \\l \(4, ' \Vi. li'iif:; N-'-"i -:;',i s 1 -■J.S.0 4 i -231 ! :!'.ii)l hT.') -2HI) tOD'.l 417 -IH-O 1 -31) -71 ; 4()-'ii :(.'2 -:i,-.r. 1 ~ :VJ '.1 i --1II-7 ! - : ■_• n J -:!01 J -•2.V2 -37-3; } 4101 WK) -■J7 !• 1 2 — ."..") 7 i -;V2-) \ -3so: » 4IJI Dili -42 4 i 4rjs jii -42-7 -21-3 J 4i:niii7 1 -2S..-> [ -31)1: i 4u;mijs - .-.:! '.1 ', -isi ; -.".'_' (I 1 -:i7.7 J -2<»..S -3.S..r J 4'.'i;7 ;«)i - ">(MI . , 1. . -20.2 -33-'J; i 4:i4i)ii:ii - l.".(i --■J.V-. ;, -.■|0-7 '. -:!:(.!.; S -20 3 -30.4; \ 4:isS' UMi - 11 :i 1 -17S \ .•.lid \ - ijii ; -li.vi: i -2',» 1 \ -40-8' J 4171- 1.711 - Hi 4 1 -:t7 7 1 -:;.')'-' 1 -4S.(I 1 -;'.i)-.^> 1 -20-3 -31-0 1 41S1 1(111 -till = -I.M 1 -111 1 ; -30<) J .... Wcinhlcl iiiiaii - l.')7J - 411 s.'> - 42 7'.l — ."ill :i."i -- Msl - 27 oH - 34 (IS \a r ■_".» Dii f ■Jii •■-•:} 1- .'!• 11 • LN :!l : -ilMH) + 2.-) .J7 + 23 00 \d + 1) 10 + 013 -r- 1)4 ^ II 0.') -i- 0(Hi + 0-OS - 07 ( 'urv. - ojs - 2,S - o-.>s - o-Js - 2.S - 0-28 - 28 |{;uii;il V.lo.^ilv - ir, s - 11 s - i:;'.i ._ ..■>,'> - 7 1 _ •>.*) - 12 2 // ;ir:.l K ■J ■ 7 - 117 - r.' .»:{:} • S2r. :{<»C)4S7.'i :iHf.25 4020 3'.2 4101 WK) 4143<.i2S 42t)7:!01 4:i40 r>;i4 4:i88 10() 4471t)7f> 44S1- tlH) W.is?liti>il int'im Ciirv. Vfliiciiy // iind K OUBIT (IK Tin: Ml'r.ClHOt^COl'li IUNAHV X Al liKi.K 1.) ■:i7.1 Vel. Wt - S-2 -;V2-4 J 12 -:i7 -1!) -31 - 2S 40 + l<.t()2 + 0-22 - (I -28 - 0-S - till MKA.Sl Ul-S <>1'' \ WHUIV. t'oiilttiuiil 7:isl V.I. W t -2(»-4 1 -45 1 -.■)3() i -2.'>S 1 - 2! ' 2 1 -■.i->0 1 + IS-f).'! - OH - 0-2S ■101 Vrl \Vl ■107 i -1!M '. -121 1 -13 '.I 1. ■:iOII 1 31-.-, ] -21 s 1 - M-0 - 2110 -r 15!"2 + 010 - 0-2S IIM Vel \Vi 742'.l Vrl Wt 31 li 31-2 32 3 30-32 13-711 I) 22 l)-2S lli-f) -12 -17 -17 - .') -21'. - 3 -2s - ti ■1)0 Vel Wt I i ^ 1 - IIM + 10-42 -r Of) -^ 0-2N 14 2-4 + 113 7 4 -12-.". + 7 41 r 23 - 0-2S + f. ■ t 7147 Vel. Wt - K + - 1 -17 i •i i •3 i - \ — ( 9 4 1 7 i - 711 + 2-2S + 0(14 - 0-28 - 4-0 -+- In 1 1 IMin.K \ I |(i\S OK rili: DUMINKiS tlHSKHV ATHIiV Mi;\srin;s ok x xrnin.v. -r.inUnni.i ■.im:i s2r, :!iMii ST.") :i>ic.s-r,'j.-, inii'i 117 |iiJii:;.VJ I 1(11 s'lll ll-'l nin 1 1 -N J 1 1 ll:'.l "17 !l l:; 'I.N rjii7 :;oi l:;iu 1.:;; l.isv. Kill I i7l 1.7.. llsl 111(1 W.iditi'.l l.KMll \-. \.: \.l...-|t\ // aiHt K 7 I.". I Vil \Vi II \ r I hi t I I .: ! 7 i:.N \cl \\1 (1 s (i \ 17 l7 1 ; (1 I s l."i 1 1 ;. '.1 \ 1 1 (', i 11 1'. s 1 11 •1 ; 11 i: :: 11 7 I7.'i Wl \\i [■I '1 I-:. 11(1 i; (11 I 1 7C. 11 111 (1 Js ■|M V.l \\i ^liis 17(1 11 '.1 ii. I l:; I I 12 '.IS 1 171 (1 lll> (I Js ■J (I IN ■ I't 1 V(l, Wl jii s ; I'.l s 1 I'l:; Jl I. Ills ■Js . 1 1 i :; J.". 1) JJ I.J Jl) s| n ( 1 J II Js J ■ I > V(l Wl :'.7 :i is 1 II (I ■ S'.l . :is . Ill Ii II I ■'■S •S II JS Uii IJ Ii 77.1 1 1 \.! Wl. i I J'.t Ii Hi' 1 II J J I :< s :;ii HI :ni :; 1 1 I I -^ :■.!■,". J - Jl-'.il - II ii'i - II Js -t 110 OHBII UK nil': Si'KlTUU.SlOl'If UlNAUV X Allill.K :v,H> I ■ 40jr) 4101 4tJ«- 4i;n- 4n:i- 4'2(i7' l.illl 4;iss 4471 4lsl s7.') cjr) 417 :{."i2 WM) 211 047 ■.m (;:ii ■100 • (17('> ■400 iiiran Va \.. Curv. i::i MliA.^l IU.S ()!■ XAUill.,1. (milihu,,! 7:il2 Vil. Wi +:i4 4 1 + ;io () ! +4.: 1 +:{i-o 1. +■-■:.■ I :■ + 4-.' !l 1 :;i; oo 27-14 (I or. -Js 4 7.-.1T V.I W I f :ij II 11 r. 11 J i.'i ■ :i Wl T + ■-'.-,■> 4 101 r^lO'O ! :;7 I 4-11 ^ t :i()-7 1 :ii'2 tiiO 1 -Ift Sf •i\ :> ■ ■_'.". s ; iSO I.I Vrl, ' Wl :;i 70 •_>7-0.>^ II ll."l I.". :i ;>:fO ^ 17 II :•.!■:; V.l Wl :•;> II I.' V :il (III ■JS M' II 00 2.S I s :-;4i;ii 2s 01 II no .'.') 4 Js 1 ,"il 4s 2 II ;{s 112 2001 010 II 2s 7.'.:}o V.l. Wt. .:i2s i .;is-s| 1 *-:!ll \ f:i:i4 -, 210 ■ 21 '.l t210 21 ii :i2ii f :io .")7 - 20 20 - lis - 0-2S -, no +- C.l k; I'rm.icx I iu\> or riir. dominimn ohskuvxiokv .\iKAsriii:s oi' X At itKi.K r„),/,nw,/ :ii,iriis7."i KHC.t' 117 ■11(11 S!HI ■u-'i oiii ■112s Jl I ll:il (117 lii;i lU.s 42(17 :!01 l:!10(i:i4 i;iss iiM) 1171 (i7l> 11^1 tlHl \Vii)jlil(>ci(y 7512 Vcl \\l 1(1(1 .■|t '.I :i(i 1 rill 7.')l!( \.l. \V( KIC.!! 2^1 .V2 (111 ()-2s id I r;il 1 i t ^12 N tit:! '.1 t2^s-;! . :;i(i 1 i;i ;i t t2() t IT-S h:!!I^2 ,-.-,i-;i r31-."i .12-7 -|S^.- 1 +:;(■>■:! 111:. 2(tl7 22 (I2S Vcl. \Vt 12 r 12 S i -r- li.'l ■ 1 S - 1 1 1 i rtsd \ , II N i t:i2->.t i -:i.vi 1 r2:M ; • :i7 1 i t;i.V7 1 ;;,s.M 2'.M7 (I2.'> (I 2n \rl. \Vl +:«•■ ;!.'.■ + 4S-.S r :;(!■(! ; -.25. ^ i r.V2-2 1 r2!l 1 ; V.l. \\l fl(|. * Id + 12. + 4'.t ■ riiS \(1 \Vt + 4il- + 10 ■ ."il . II f:il + IS- ' .".V 42() ^ :ts ■ .">:( r 4;! 7:i 211 ■4(> - 2'.»-2s - i)2.") - ()i:i ().2s - ()2,S + 11(1 + II 7 i- ',2 1 |-4() < fl-"i 1 •-4:t ■J + MS 7r)s:. \rl \\t. -t 11 (i r ill 5 + :!.-. (I -t- lill l\ t ill r :is 1 h 52 5 t :is 4 I :!(! 1 -t ;!7 2S 4 ^- 17 ( -t 47 A -, 42 ( 4 1 14 r :((■,■ 52 211 U - 2s.2(i (1-24 - (lis 2S - (I-2S + < OKHII UK IIIK >IM;c I liiisriilMi I'lNMiV X MUK.i: MKASflMS i)| \\ll;lci1. <;>mI„U,I :i',Mis KMH) 4()Jl) 41(11 4121 iV2X 4i;il 414t 421)7 4340 4:i,ss 4471 44M ,S_'.) sir, 417 ;i,-)j Dili Jll 047 '.••_'s ;j()i (■>;i4 KM) (')7<1 4IKI \VciKlilr;. f:;i;- +:(:>• +:h +.^11. +29 + .M +:is + 42 i '.' 1 J 5 i (I 1 II ', 1 1 h' 7; ■1 1 .-,' 1 1 .". 4 1 +^h■^^ 1 +;ioo S 11- 111 10 2S 1- UiT) + i:i-o 7i;2i Vrl. \Vt Jll O 1 I ;'.2 7 1 1 2> n \ I :i2 ■ I 1 • 2li 2 1 ^:i2x 1 + :iiil 1 +:ir,i 1 2h07 111 l.-l 0-2S 0-2S (i:i o:J \rl \\l f:i2s t 10 II t ."0 I t Hi I. f .".2 r, • :is . 2 , HO ;i + 40.S + 2.S-S + 40 2 t-.Vl 7 + jr. 1 i:> (i:. IS -40 2S 2,S 20 ■ 1 17 4 V. 1 W I \ . 1 W I V,l W'l. The period is roinarkahly lung fur an oaily tyix- star, ami it sn liappcns tliat ttic (il.servatioiis taken at the Verkes Ohservatiiry fall almost at the top of tlie curve, so near this point, in fact, tliat in tlie preliminary elements it was imiiossihle to decide on which hranch of the curve they should lie. For this reason, and also because there is generally a systematic difference between radial velocities obtained at two observatories, the period was determined from the Ottawa observations alone. .\- it turned oiil. the inclusion of the Yerkes Observatory plates would have yielded iiractically the same result, for the final orbit pves a mean residual for their jilates of +:? \ kilometres, which is just about the ditTerence usually found between measures made liy the two observa- tories. Seventeen normal places were formed as (jiven. It is unfortunate that the nenulne mimnuUii i.- not ir.r.rc iiif;iy !!!-;en ..1. ..( ..1. IS IM Hill U|i'\^ Ol Mil DiiMlMoN iiH-l II \ \ 1 1 "K ^ ,„ ,1,.. -t;„- a. I Mu, \r ..I.MIA. Ml al m.,,,.- .■ I. m ll..' l.iMnv ul.uli can !..• >" ell. .-til a- t.. .1. 111!.' 111.' n.-naluf iniiiiimmi a> wi'll. ■YU, pn.lin.iiiary .-l....,..,.!- .•h..M.n l,.ll..u th.' i...in.al i-lac'- a...l lli.- -ur.T.-.v -trps 111 til.' lca-i-~.|iiaiv -oliili. M art' ii'<'..nlf.l. M>l(M \l. ri.Ml > No. .1. ill, It. I'.\ I : I I i:. hi 17 riiiiM' lni..i l'rilllli..l:ll\ \iln W.IKhl ■-MJi.llT" s I. "I 1 iv". J ■li:i H 4117 «.» 4!i-.' I .VIM ."i7l li l'i(l<.l I) 7:tll :) 7.il I SI 10 I s",'. '.. s7'. 1 !.Jii 7 '..is 1 ',»s7 - IDs s li>ll 1 JUi -' Ills I'.s 'I :..M 1 r,i\r, 1 .iiij li I'liii II nil ;•. i:vj 1 171 I Jill '1 ■j.".ii 1 ."..1 7 .;i'.. 1 :i.-is-j -1".. - Hi 1 •> ■' . 11 t 1-' ."i 1- s 1 :( .1 ■Jl Hi ■y - :i .'i + ■-'•1 4 li'.. • II 1 . . ( ' 111' I'll luiiiiiiirv I'liKil + 11 -:m fit 1 1 ;i -1 li O ."i + ■.; t -1 :i ^ II li -o '.( til- 4 +■10 + »■■> -d-J -1 1) fO » +ii:» - ;t s t-n i . II !l -1 t f 1 li ^ 1- ;( 11 1 fii ■S fi .> .-(1 :i -1) "J -u () (lay- T = .1. n. •-'.»■-'<>..■'•-'•' , = -jn A" = -M .') 7 = -(I II'. H -- (I .'^.vl.V. oiiiiii or iiiK, -I'll I i(i>-i iii'ii nl^\l;^ \ vri.'n.i. 10 (ir I it\ \ I |i I iM \ I K i\s U.ml.l III II IJ l:; 1 1 15 It; 17 IKKI IHKI mill IHIII I II II I I II II I mill I II II I IHIII I I' II I I II II I III II I IIO:i I 11(1(1 I III II I mill I IHIII 'lie, .■iii.'i WIS , S."i1l I 7l'.!l . ii:,i ■ ii'i Ijii I'.n; 'iiij 7s;t 17.". |i.7 fill f-H7ll f .-ill I -riii;! WIlCIC t .•.:tl • I 11117 iil'i 71 I ii77 .".Js I in:, •III! i:!.; . .M -r -.SI.'. I + '.iv.i 7111 ! -'17 - iins - r.ii;, - s'M'i t I.VJ 7H.'i S.V.I |:t.-| : 17 I nj'i I I II I 1 1.' I • .M + 112:. I MM ( s.Vi ' S'JIi 1 7HI i nil k nil .r = (iy .'/ = il'< z = A(/.' j> — Kdoi 1(100 K l,JII 7.S7 7. a I hi; ;i.ii .".71 I I H II I I ."l"i I -'.Ml .•.7 1 • 7:iH 7s7 7l:i iliii ■."].VI • is.'. - :U7 It'll mil (l.'.s 1171 II-',", (l.",s .||||7 ■ i:r, I. ",7 11,.", li,:i ■ 1 .-,.-. I. '7 I .'I . .1 7s II I.J I 1,1 I ",.', I .;i II |;i II SI I I is II -'I, II Is II s'l II .".-' -II 17 n :t II :l II I II ^ II I, II s II I II I II J II I II I II I. II 1 II ."i MiKM.M. BilWridN.- ,S 400.|■ +l (lOl// f i!i:{ic + l-4.-)!lyi - I K ;.')(/ +:?-oo:{.v -1 *V.\Sz -1 ■(«.->/) 4(l".)S()f/ +:\-7i)Sz -0070/1 + 4-.'5f.7/^ -O-O-Jtw -4 (»r)0(/ + :5s = -fO■•2'.t7/• -f 1 4:w = o -0■lll^ + uo:? = o + 0()l7r -1 2t)7 = (» + 0-02S,' + 1 O.VJ = K »•_'•-':!/■ -0 \X\ (1 Wlii'iicc x -= +()(ii:5 ,/ = _(|.(!ti'.» Z - -0()2") /» - -]-()■ 1>.I7 (; =• +0 ■!(;!• ,■ = +1 OOCi 'h - -1 (t-Ol kill ,IK = -0'.l7l',l clu = +o°-.-yj dT = +()-7S(l;i\ dn = 4()"-()04ir_' H) I'l III ii \i|ii-,^ i>i iiii iinin\|iis MH--I la viipin I l\ \l I II MINI,- /' m. (,,",.", Hi ■ .", _'li ihi>- T " .1. 1 >. _M-'(i.ti_".l 7^ • '.I ."«(i tla.v- u) i:i.'> .VJ ■ .". J n 171 ■ n iiji, /\ jn ;,:; km ■ u ■'<'i Km. 7 ^- -(I I.', km. ■ II :!.■> km. ,1 -ill / |sj.:{(M) (MHI km. ///,' .-ill' / (//( + »/l)' ■= O-.'iti '0 •riiiKD jtiiii'* It will lie iKiticc'il tluii till' liiiKiiv (haiai'tti- wa- Mniioiiin'i'd from tliicc jilatrs, whicti llic nrl)it -iiou- to I'all iicai itif i'|ii>cli df jxi-ilivc maximum m-|. radial '.cliicity curve)*. Ill tlic iiilcrv.il cipvcrfil iiy iIicm' iiialr- till' \aiiatiiiii -lioiil.j lie -mall and the vcliic i- I'lincd in i iiiiijiKir that tlirir l- aiinlln'r pi'liod -iiiicriiiiposfd iipnli tiic one found, or I'l-c liiai ihc aniinmici'd variation mean- iiotliiiij;. 'I'lic spectrograms lia\(' been remeasiired at I lie ^ eike- Oitserv atory. and I'rotVs-ur I'rosi (iiids no reuson to doiilit that the ralin'' indicated liy the \clocilie- i- real. \\C lia\c lieeii unalile to liiid a period for ttii- variation. Several i(ls would liariiionize ^onie of the iai>;er residuals and so reiliice the stini !"/ the residuals from the main orbit well enough to warrant its iidi)|)tioii. Coiisiderinn the elements of the -ystem as pulili-hed. the iirobalile error of a single observation is ;< ."> kilometre-. 'I'hi- i- larger than we u-ually (ind for frood line stars by about 20 per cent. In the .\slr(>i)li!isi:;il .hn.nnil. March, l!ll,"), Dr. Schlesinner ()ui)li-lie(i a niettiod for deterinininn the periodicity in a series of obser\ations from a consideration of the distribution of the ob-eived velocities, 'riiiis, for example, if we are dealing with a I'ircular orbit, more velocities should be found near jxisitivc maximum and nep;ativo minimum tlian near the y line. If the residual-^ are due entirely to error of observation, the velocitie- amund the 7 line will be most iiumeroii-. ( 'ii>ve> are published giving the expected distribution of the velocities for orbit- of various form-. In these curves some allowance has been maile for the ctTect of probable error of nieasiin-ment upon the re-nlts. Some time |>re\ ioii- to the |)ublicatioii of thi- article, the writer tried to iiiiike use of the same method in Kettinj>; a period for the binary I'J I.acerta'. In this case the velocities were distributed very much as one would expect if the ob-erved ranti'" were due to error of measurement alone and yet. -ince the total obser\ed rarifie w;.s oV(>r sixty kilometres, theix' could lie no doubt of the binary nature of the -tar. The conclusion •'1 lir iiiiriiiiil |il:i(T friiiii till' (ilisiTV:ili 1- iiiilicMi.'.l liy a I'irilc- iiml cro.ss. iiiuiii i>y inv. -i'i;< I iiii^i ui'K iiiNvin x \i iiii;k 21 wji- llial till' i'\|ii'(Iiiliiili WH' iilT.Tlcil \('r\ niiicli ii> iTlnr- uf in<';i-iirfliiflil. Ill al'plyiiiK til. Ill* iliml tu the prc-rtil t.ii- I !i;i\c !:ikcn -oiiic care In liinl 'Mil jii-l wlml (lislril)lllinll of \clnclli"« Wf -linllltl cxiircl wlicll holli fjictiil-^ lirr lllk.'tl illln ucculllll . I,rt US -iipp.i-f tli.'it wf an- (Iciiliiin witli ii circular il uho-c ran«i' i- fnun plu^ Icii kilniiic'rc- to iiiiiiU' Icii kiloiiicln-, ainl liial llic prdialilc crmr nf aMircinciit i» r. I.cl 111!' vclncitic-. it' llicn- Were /.Wit cnnr ..f incu-urcrnciil . which wuuld he hclwccii Ihc limit- phi' ten In plil^ liiiu- he (Icliutcii l.y u, phi- nine U, pin- einhl he iu- sl\ hy ( , . phi- Iwn In zelu l.\ /'. I.el ll,n- fimri /eio 111 lllillll- t\\(i he ilellnliil hy /'. ai|.| -' i nil till llin-c hetwecll IllillU- llilie illl.l IllillUs let! arc (lelinteil li\ n'. S )li(ll\ . let II- -uppn-e the raiine ill the nh-ervat inii- i- illle tii ermr (if Ilieasiireiiielll alnlic, and let the vclncilie- which wniihl lie hetweeii the liiiiit- zern In phis tun he (lelKited li> /. hetwcen the liinil- phi- tun In pills fnlir hy J. etc. I<. r. ale ea-ilv cniiiputc'l analytically nr jjiaphically. The graphical nii'tlind has the iidvaiitane that it can he applied tn any radial velncity curve, while the analytic exi)res-inn fnr JI ,2\ 1.1 - 2\ + l.'ii til -> Jn -j '.'S Ii, - .,(1 +:»\ to r-^2 + 3-J to riil oiisd ■07.");; ■Oti:t7 •017'.) 1)7! 15 ■()7IK ■(i(i2:i •0474 llMiil (i7j;i ( I.V.I 1 (14111 I1S7S ■(I(i71 •(l."i."i4 ()441 ii7;i:! ■IHi04 •O.'iOil •041.-1 0."i7l (l-l'.Ci •01 IJ •o:W7 ll'J'.l.'l ■difSI) ■OHM ():i.-iii 1(1(11 (lii'lli (i:ii,^ •():i2! 1 M r_'."i ■(ii7:i •O-'.'iS •()2.S4 1 ii i( 1 1 ■00'. Ill (1201 •024'.) ■ (!o."i:i (ll.Mt •021.^1 (lO-'l •0111 •01S.-1 IKHI'I •007!l •0 !.-.;{ •IMMIJ ■ ( l( l.'2 •0124 OOOl ■0(i:il •0100 ■OOl'.l •(HI7'.) . , , 1 •0010 (MKil •497H •5004 •49ti3 ■47.S4 111 the laliu'hitcil rc-iilt-- tlic imiiilicis arc ;;i\('ii to Iniir ilcciiiial i)lac('<. ami ii.s cacli \va> iilitaiiiiil !iy llic -miimalinti nl' scNcral t'actiirs, cacli (if which wa,-: unly ciiiiipiiTod to tdur placc'^. ihc la^i ligurc is imt in {fciicral currect. The >uin of the columns given at till' liiiitiiiii if cxtcnileil til iiilini!>' shmilil total oiu^-half. sn that the addition of the columns ^cr\(s as a partial ciicck on the work. In tiie ciirxe^ the n'>^<'i^~:i'' :'i<' ki!oiiielre>. any point jihis .r indicates \-elocities lying lietween ])liis .(■— 1 and . Ins .1 + I and the corresponding ordinate shows what fraction of all the \cloi-iiic^ will lie lietwein the^e liiiuts. it will be noticed that curves for the I'atios ',, ' ! are \'■ 1, and if r e(iual liti kilometres the computed r will be S-2. The computation becomes a little uncertain for r equal 10 on account of some velocities lying beyond the computed values. To apply the results to X A iriga-, we have computed the distribution of the velocities on two l)ases. In the tirst the residuals are supposed to be due to error of mea- .-,urenient alone, in the second they ire suppo.-^ed to b(> due to a |irobable error of measure- ment 2-84 kilometres, combined with a binary wlu)se eccentricity is zero and range S-.')2 kilometres. In the table below, the hrst hne give- the distribution of the observed residuals, the second, the comjjuted disiribution on hypothesis one, and the third the computed distribution on liypothesis two. km. 0-1 km. 1-2 km. ■2-.! km. 3-4 km. •1-,") km km. 6-8 14 1.') 13 I i:i 13 I 13 I i ( i 11 U li \2 11 it 12 n 9 1 km. 8-10 km . 10-00 t 11 1 7 6 ,s 11 1 ,5 () 8 11 i 6 r> 24 1>1 UMIAIIONrt OK THK UDMIMON OBSEUN ATOKY The two hypotlic-f- siivc iiliiiost idcut,. :•! .li^tiiliiitions -vhcn tlic luiinhcr of observed vclncitics i> limited, in ihi> ca-e ss. In other wonls, an inspection of the manner in wliich the velocities are distributed would not eaal^le us to detect the presence of :> velocity variation three times the iirobable error of !iiea>iireiHent. The above residts are deduced for circular orbits oidy. They have to be modified slifil'.tly for orbit- of hie also the elTect of error of measurement i^ to ma-^k the i)resence of the orbital variation. The oidy evidence that we have of a thiril body in the sy>tem of X .Vuri^ia' is the ma;xiiitude of the jirobable error obtained for a siiifjle velocity. If we assume that it should be -JS. thru it would b(> necessary to a-sume also a ran^e of S-.") kilometres in or wa found -liowinii they .>()uld yield a smaller ranjic for the curve, .\fter the completion of the orbit as given in the i)rec(>ding pages, the velocities from the // and A' lines were grouped into ten normal places as follows. NOR.MAI. l'J,A(i:S ton // AM) K LINKS Weight ! O-C 10. ■Jli.lilt I i.")i :! ■Jirj- 1 -M'.l 11 ■J77 II :;ii-.' !i 111 -• ',7:;-t M< 1 rui-2 I'J't s 17(1 >■)- :;()■.> ;'.js (.;, CIS s .)!«.■ (i - <)o - OS 4- U-."i r 7f. -rlO a + 9-9 + 10 OK 0-9 1 () i:i 1 -J 1 :> I I It -2 -a +•>■.-> -O-l +.■5-2 -0 'J +2-,S -0 li -19 -0 1 + 0-7 I'reliminaiy element- lo -ati-t> the c place- were -elected, the jieriod. eccentricity and o! were taken as previou>ly found for the t,ther liner-. A solution was carried llirough for 7 and K with the re-ult, y — + 1 -o km. " ((■4ii A' - 1(1-47 km. -( -So Th.o radial ^e!"citv curve for the H and A' lines is giv n on the same diagram as that for the (jther lines and i5 drawn with the finer line. The ditTcrence between the UKBIT OF THE SPECTROSCOPIC HINAKY X AUKIO^ 25 velocity of the system obtained from tlie // and A' lines on the one hand, and the rest of the lines on the other, would disai)pear if the a>sunied \alues of wave-lengths for tlie calcium lines were increased ()()'22 tenth-metres. The behaviour of the calcium lines in stellar spectra has been a subject for much speculation and investigation since the orbit of S Orionis was published by Hartmann.' 'riie chief facts so far brought out may be condensed as follows: 1. In eight stars the calcium lines are constant, or nt.vrly so, and are sharp anil narrow, while the other lines are more or less diffuse and show a large range in velocity. These stars are given below. Niiini' Range of Hroad I.ineH Remark.^ o rcrsci r; Orionis. ^OriipiiiH . S Orionis IT Orionis St Orionis B Scorpii Boss 1)1 (■-'. 23 .-.lO (^ep km. 3 :iso HI 224 r, 1<' 4 lU 290 .5 210 IV.> 2NS .1 ■Jt)-9 B 2H> .^ ■2H-r, B2 2l>-4 .5 30 5 HI 220 ■5 59 t; Bl 2.51 Liik Ol)s Hull IM I'.A.O., Vol. HI, No. 21 I.iikObs. Hull. LSI I'.A.O., Vol. 11, Nu. 14 2:{0 P.O. (unpublished) All the stars in this list are of type B2 or earlier, and, moreover, if we form a list of all such stars whose orbits have been determined and the A' line measured, we find only one, V Orionis, showing a large range and not included above. Future orbits may add other exceptions. 2. In several stars, the calcium lines are known to vary differently from the other Hnes and in four ca.ses, orbits have been determined from the H and A' lines, i.e., for £ Persei-, type Oe5; 9 Camelopardalis^ type B; xAurigae, .ype Bl; 12 LacertaeS type Oeo. In the last two the amphtude is probably about one-half as large for tiie calcium lines as for the others. There can be little doubt but that future investigation will reveal all gradations from those in which the H and A lines are constant to those where they lia\e the same oscillation as the other lines. .'J. In three stars the calcium lines are shaip and narrow and are shifted about one- half an Angstrom unit to the violet. These stars are, -^'ersei, type Geo: i Orioni.>', Ivpe B: p I-eonis'"', type B. There is evidence in these cases that it is the hydrogen 'Ap.J,, Vol. XIX. p. 2«8, 1904, >l)om. Obs. I'ub., Vol. I, p. :)55. 'Ap. J, Vol. XXXVII, p. 1, 1913 •K.A.S (Jr., NovembBf, 1915 'Ap, J . Vol, .\.\X. p «:(. 1909, •lioio (Jb« Pub,, Vol I, p :«", 20 ,,„,,,r.VT.uNS .... iHH l...M.NmN .-BSKHVAI - -UV ,,if.., ,„ tW red ana .hu. ,l.e ..l-iun. Hu-s .nay be m the.r and lu'liuni line- tluit an- normal positums. ,;,„....,•,. hn.ad and no <.il)it has IxM-n deter- ,, ^ Persei, tlu- hydrogen and l.ohun. hn >> a. 1 oa ^^^^ ^^^^^^^^ ^^_^^^^.,^. .^ ,,i,,a from then., aUhou.h ,hey ^^^^' ';; ;^lJ^2eru.r^<\ fron> the // and K Hnes, the true velocity ot th.- star ,H,hl,.hed. hut if we lak.' the n.ean of !:t=;:;r;;:r,;r:"^i.t:i:::::;:;.:;^. -»- - -- the most pi-ol.able. , , , , , , ^„„i. but the mean velocities are, for the N-.. orlnt ha< been pubh.hed or P >;->'- " f.,, the solar motion plus five. .•aU'iun. hue. pin- -en, for the --;,-;- ^^ :!::,. .Irdahs type B: . OnoniA 4. In seveial Mars k( a^^.ope.a , > < > ■ ^j^^.,,^. ^j,,^., „,,t ,eem H,, the ..aleiun. hnes are 4.arp and ,he o 1 n. ^^^ ^^^^^ ^^^^ ^^.^^ ^, ,.,^,,, ..'he n.ueh d^e.-enee between ,he ^ ;"; j;;^' Vil';;!;: ^ne of de.ree. The difference l>ef.veen the.- sta.^s and tho. - ■ . ^^.^^^^^ ^^^^^^ .^^ ^^,^^^ ^.^,,, , ^- ^:r ;■ r ::.:::■::; ■:• r i:;r:.an ,. said concemm. t. behavtour ;5 t:r;;;;.: ' Vir.m^ and . .... a. r^o^mat.. ^^^^ ^ ^^_ ^^^^^^ ^^„^ ^^^^^^ ,. ,i-i,,re seen.< to be no exception to the nih • ' '^' ,^^^.,^ ^^,^, ,;,,,. .„a the other hnes b..ad, t^-;- " ;^' ^ j :^:;^;i,. ,, th. hrst. the ^l-hree theories have- been advanced to - ^^"^ ^ ,,^,^^.,.^^ ,i,, .hserver and tZr :::'r:l^;:;^'l sn-a ;l :;™^i ^^e star or stars, and in the Ihirr P.e, ua are a.r.bed to =;--|;- .;;-;— ,,_ter of the H and K The first hypothesis accounts for th ^^^f^^^^^.^^ ^vhv should the calcmm H,H.s n. class 1 and the fact that ^^y yf'j'^:'^;^- We have exan.tt.ed several ..h,tuls always lie in front oi a star of ^vpo ^^^J /; ^^^^^^ ,,,,,,,,y. There may be huer H-type stars without hnd.n, ^'^ ^ ' J ,' ^ ,^^. ,,, ,ff,,t, hut the phenomem.n some stars later tha.. Ui discovered ^^^^ ^ ^''^^^ ^^, ,,,,, ., ,h.ss 1 the velocities .eems to be one connected with early speet al t> po- ^ ^^,^^^^ ^^^^ ^^^^^^.^^.^^^ Xlded by the calcium hnc^ are verv --r lie ^.h, t> < tlie^V ^^ ^^^^ ^^^^^^^^ ^^^ ^^^^ ^.,„,^. ;j.,„, ,,,t argue Mron.lv either apunM or f^ J ^ ;' .^.^..^^^^ae,. :i require an explanation h,w velocities of the early U-type stars. 1 h( a ^ phenomenon is too ""■ -': "r'T"::;:;""-: :::,:■;::.;;;;:':;" :t^ » .-. .-,* .- .... complex to be aiioum-.i u i . ment. :Unpubliat>"l '"""*'"'"■■"■" •Ap J . V.ii, XXiX V ^■=' :•"' OUBIT UK THK Sl'KCl'HOSf'OPir BINAKV XAI'KKI.K 27 The sccoml hyijothcsis may he proscrtcil as follows; I eV V\g. 2 Let A and H (tig. 21 ho two -tars or the tsvo luirlci of a binary, iv.ui lot the gases be condensod about these. It is known that ealeiuni oceurs at very hi^h levels in the sun, and let us suppose that the e()uidensity layers in the caleiuni vapour about the two stars are nearly spheres. The ealciuin cloud will rotate about the eoiunioa centre of giavity of the two stars in the same period as they revolve about each other. If A is the primary star and o'.ily one set of lines is observed on the plate, we ne(Ml concern ourselves only with the light from A. The light from the photosphere gives the c(mtinuous spectnnu. and as it passes through the cooler ga.ses, hydrogen, helium and calcium, has lines from these elements absorbed. The absorption of the calcium takes place when' the element is very rare, which accoimts for the narrow character exhibited by these lines. The absorption of heliiiin and hytlrogen must be supposed to take place at a much lower level. Assume that it is permissible to s])eak of effective levels at which this absorption occurs, at a height D for the hydrogen and h. iium a id at a height F for the calcium. At the time when the primary is moving toward us with the greatest velocity, the points at which the calciimi absorption is taking place are rotating then as always about the point (' and so are moving nearly across the line of sight. Moreover, the different points are all moving at about the same rate toward the observer, thus maintaining the narrow character of the lines. The points at which the hydrogen and helium absorption occurs, exhibit a wide range in velocity and give the wide character of the lines anil the high range if the inclination is nearly zero. If the inclination is nearer to ninety degrees, the hydrogen and hehum lines would be >liarper and give a smaller range. This tits the case of 12 I.acerta' and X Amiga-. There are doubtless other factors not understood which may contrii)Ute to the wiil(h ol the lines ob.served in other cases. If the calcium cloud were extensi\c enough the calcium lines would remain nearly stationary, at leiist the amplitude wr.ald be sniall enough to be 'nasked by errors of measurement. As the cloud condensed, the amplitude observed in the // and K lines would increase, the txa-t range ilei)ending on the degree of condensation of the calcium. 28 I'rUl.lrAIION.s iiK nii; DoMIMuN ohskiu aiokv 'I'lii^ tlicoiv is capahlc of cDiisideraljlc adjust iiieiit^ to iiiect varyii>n (icmaiicls, and siiKK<'?^ts fiitiiic tyj)c> of \aiiations that should li<- discovered. Tlic third liypotliesis ascribes the wide clmracter of the linos in these stars to an()iMal. '_'. The ami)litu(le >liown by the calcium lines i- about one-half that for the other lines of the spectrum. .'i. \n analysis of the (iirtereiit ca^e- >o far known where the calcium line> behave (litTereutly fn ;n the other lines ~liow> that the phenoineiion i- one of type, and i- best exi)lained by the presence of calcium in a cloud surrouniling the binary. The absoriJtion of calcium takes place at a much higher level than that of the other elements. 4. The residuals ^Wcn from the simple elliptic orbit were examined to ascertain if there minbt be a third body present. Xo secondary j)eriod was found, but the star should be observed with higher (lisi)ersion to test this ])oint further. ."). The method of detecting periodicity in a set of observations from a consideration of the distribution of the velocities was tested. The value of this method is greatly interfered with by the etTects of errors of measurement. If the ratio of error of measure- ment to range in the binary is as great as one-fifth, the resulting distribution of velocities is very much the same as would result from errors alone. If the ratio is as large as one- third, the distribution is almost ideni,,al. It is in these very cases that the method is most likelv to be needed. notuinion (Observatory (Tttawa .'une, nilC). OKBIT OK THK S1>K<"I li( IS( OI'K HINAIIV X Al HKi.l': 20 -20 /' / 'i Days 100 *" ^ WO 600 TOO 800 900 too J Kadiiil N'clcjcity Curves of \ AiiriKX- M) rt HI.K A I IONS LN(; I'b 1) Tin> (•l(Mii('iit> (if llli^ l)iiiary wen' puhlishcd in llic I'nhUaitions of Ihr Dniiiiiiinii OhsrrmUirii, \' for the other elenient^. In the following tal)le the ditVerences between the velocities a^ given liv the A' line and those j;iven hy the other line^ are j;roupe(l accor7.S7 - 4 1 M-2S - :i!i u;);).') f 1.V7 tl270 +- 7!t ti2t)2 + 171 llitil!) ► .v:i H:i4H -iii'i tl2sl ^ 1 S (i2'.ll + l!l-4 iMll'.l - !l '.1 li.'lOl 2 !) Ii.i42 t .A ■ () ii:i(is - 2 Ii I'.fJil :5:;i ti!t!t2 - 2 tio31 -r ti 1 »■>;<.■)» i + 11-0 1,407 tidds + 3-8 6542 - 4 1 Ii4.-i4 - :.-4 r..v.'i . I2ti 7(i:i:i - <»-4 7(HI1 f 14S 7023 - SI il.").")7 r III 7ii4:i + 11-9 1 7(12(1 -L14-2 717.S + o;i 7(rjii - 1 11 7 is:! r !l() 7177 +22r. 7210 + ll'>-0 71711 -l:i :i 722'.' - 12 7214 (-ll)-9 7244 - 4 4 71S2 -r- 1 2 7243 + .V2 72(11 -12 2 7251 + '.>•!• 7211 - ll-.S 72tir. + t",-7 72 1(1 - 2 .i 7270 t-l.-i 72lis t- t 1 7203 _ ■».'» 7:t(l2 - 2.-1 7300 t-KlO 7.'U(» -IC.-S II (1 - 5-2 7:ii;i r2H-4 7:)ll .Mrmi Mean + 1-9 i Menu + 9 7 Mean + :ir, 1 1 , The weighted mean of all th(> residuals is iiositive, due to the value of the wave- length of A' used. If we remove this etTect. the resulting means for columns I, 2, 3, 4 would read — 7 :i km.. — ()-2 km.. +7ti km.. +14 km. The semi-amplitude of the velocity eurv'e as I'ouiid for all the line> was lti!t2 km. Th(> amplitude for the A' line would he about 7-.") km. less. 1 )omini.)n Observatory Ottawa May, 1016. i 3 T33M OODblMfiD fl CAl NfT 403 P04-01 t5 m ;oggfoi