;62 



NATURE 



[May 11, 1 *^ 1 J 



tributary of the former, and both draining ulti- 

 into th<; \ iikt>ii. 1 he cojiU arc- of Jurut>ht»- 



■11* age. Ill' plu --iiit;! .i|>!i\ .md n.ifui.il lii>tur> <»f 



iit arc d> 



|.|!«htf(il. 



cultiva 



M 

 iin{K>rt 



I ' 



ant 



111 



im-moir <>f >" 



ih.- II.ilil.uil..t 



4"<' |'-»K "• 30 



i| n.iiii r. ' ' :;iriu. 



I inti. 



\\\' . i)li;m 



■ s, Willi inclusions of anij)liibolit'_'. 'J he 



conchi^ive reasons for rffjarding the latter 



.u..^->. > .!> il. rived from thf — * '- "a;iIIs of the ^rnnit'- 



hatholith ; th*> blocks ftU in lu.i, and jiarlook of 



;l~ •nuIisi'iiui'iii nKi\>inMi:~ I ;'iiii'ni!\ lli- \ !■•- 



l>\Hli>N, , . .1; . i I .H ■ 11 M > 1111- <iiiil.nl- 



alterati<>i ■ ^^ranii'', wiih iiirhaps some 



intormiii^ _, ^ js niai^iii.i. 1 lii> is, of I'oiirso, 



\>,hat has lif.-n uif^iMi in many <>lli>r ai^ .is ; lull llii- limad 

 '. .\()i>sur's in this,- undul.ilinj,' C.in.idian Kinds ol'fir un- 

 usual cppor tunii il s tnr di iiionsii-.tiidn. M.in\ <)ihi-r types 

 of I'l \ si.illiii. 1 o, U .III' d' srrilii (1, incliidiiii; >\inili's with 

 roninduin, and tli'- who!' iniini>ir is onr (d imnn-ns.- intir<st 

 io ihi- pitrdi^raplii r. I hi' (uiunduni is woikid roni- 

 iiii 1 li.iih ( p, ;7 I I. 



^l:. j. \^\' — 1" (l.siiili.s Si. l>iimi> Moimiain, in 

 •Ju'Imi. Ml Ml moil- -. a mass nf idirahasic i;.;ni-(>Us mi k 

 intnidfd jnu> Ordwsirian rm i<s, pi-(vlialdy in Drxonian 

 times. Mr. !). Dowlin- d. .lU, in Mi-moii- .s-j-;, with tin- 

 promising ti'dd <>f Cr. lari oiis and Caino/oic c.i.ds al 

 F-!dmonton, on iln- S.-iskatcln-wan. in ilir north-w.-st. 



Memoir 3 is a i|uari(» h\ Mr. 1.. M. I..imhi' on 

 Pala'tmiscid llshrs from thr Alh. ri Shali's of Xi-w I>runs- 

 wii'k. dill' .author corridali-s this.' hi-ds (p. i.^) with lh.< 

 Scotch C'.ilcitVroiis Sandstom-. Ili- timin-s. amoni; otlur 

 spet-imi'iis, till' ivp.s that wim'-' di'si-rilu'd h\ ('. '1 , J.u k- 

 son, wiihmit illustrations, in 1851. 



Mr. (". I). Walrott (Smithsonian Misn 11. CoIIih lion-. 

 vol. liii., No. 7. 1010) has cnrriod his siudi.s of Camhrian 

 Stratigraphy inio the I-low River \'alli-v, .Mlnrla, ("anad.a. 

 a hi^ld\ pii-lurtst|ui- .and nioimi.iinous n-L^ion, wlun' Iv 

 finds th.at Hv hasal Camhrian In .Is r. si imronform.-ddv on 

 unaltered pri-( "amhriaii shales and s.-mdslones. 



Perhaps wi- may mi-niion In ri-. in conclusion, ;i jiaper 

 by Ml. K. (iuppv, ])iihlish,d in (".inad.l (Trans. Can.idian 

 Institute, \ol. viii.. p. ;;;,), on •' 'I'hi' r.eolofjical ("oiinec- 

 tions of tlie (^arihl an K.eion." Mr. (luppy, writing 

 from ^ Trinid.ad, discuss, s de.p-water C.iinozoic heds in 

 Jamaica and other isl.inds. and are;ues for a former " land 

 connection hitw., n the Carilnan and North .\frica and a 

 sea connection hetw.en the C'arihe.an S.a .and the I'arinc." 

 FM.th thes,. pr<di;ihly iiass.d awa\- at the close. <,f Mio,-iii.. 

 times. Mr. <",uppy has a w.iv of .alxdishini; douhle letters 

 in ejeii.'ilc names, which mav !>. .Xnterican, hut is h.irdh 

 fair to rheir orii^inators. G. A. J. C. 



PRESSURE jy STELLAR ALMOSPHERES 



"Y^ITHIN the last fifteen years the spectroscopic equip- 

 ment applied to the study of both laboratorv and 

 celestial investigation has been "very materiallv modified 

 both in dispersive power and design. ' Tn the carlv 'nineties 

 there were very few of the 2i-5-feet Rowland concave 

 grating spectrographs in regular commission for terrestrial 

 research, and it is prob;ihlv snfp to sav that no stellar 

 spectrographs were in i direct spectra comparable 



m dispersion with Row ir spectrum. 



The transference of Dr. G. K. Hale's sphere of labours 

 from the Yerkes Observatorv to the new solar observatorv 

 on the summit of Mount Wilson, Pasadena. California, in 

 IQ05, however, marks an important ejHK-h in the progress 

 of spectroscopy, as from that T"., 

 successful application of liich di- 

 thc problems of celestial and lerr. - 



NO. 216;. VOL. 861 



be dated the 

 ctrogrnphy to 

 lificntion, both 



: solar !• 

 i cvideni' 

 i>.v.....ibly initial 

 solar photograp; 

 the relative wav 

 tiun of .1 d' III! 

 .iiinoiini . i| I I >/i 



adaid map l^r future; rcf<:ici><.<., I. 



)an\inf; the ftun-4>}>(>t vorticck, the • 



"in ciKJW'moUk nias« oi 

 d diiM:ui»»ioni> may be 

 lion of certain of the 

 litics were noiicf-d in 

 , iildii .iling ill' I.J), r.i- 



th. 



uh- 



th. 



d;llerenLv- 

 found fron. 



motion, ih 

 between A 3741 and A 

 could be classified lo 

 lines, calcium ill, l\, 



\l: ■ ..ppr 



naDii. 

 lines 



I |ij :; ::!!• s -.sere r.,l.itae|v 



I li lindj compared with ti 



' .11 no-. In lyio Hale and .•\daii..s .i-^n.o'd 



1 long serie> of deterniinatioti;, of the**; 

 p-nts made wiili llie .spectrograph attached 

 scrvatory (.4i(ro- 

 .\fter eliminating 

 • rotation and orbital 

 lination of 470 line* 



oe; residual d- ■ ' -v 



xtent. Thus t 



•dium D, and in „ I) 



displacements, and this was 



the intensities of which were 



greail) .stieugih' ■ of the sun. The line* of 



titanium, v.inad adium show considerably 



sm.iller displacemems man tiie lines of iron and nickel. 



I he elements of high atomic weight, such as lanthanum, 



cerium, in tfeiiiral evhililtid verv siti.iII flisrd.-irementS. 



The rnJhi- dedly largtt 



shifts th.-i;-, 



.Ml ' suggest ion that they are 



(.luseil in different parts of the 



sun's .iini' -p ■ . : I ■ ' ;i. liius be readily seen how, by 

 a cueful siud\ of this, interrel.ations and the laboratory 

 v.ariaiioiis l<'..>e . ■, ,• :it-,i,., ,i:if,r,.ii modes of treat- 

 ment, We ! at a satisfactory 

 e.xplan.atior, ■ - .r atmosphere. 



Now to ;li. .,^;:\.p:,- -;. ;-: il,.- .sun is simply our nearest 

 star, pri s, r,-;n^ ;o u- -pvcial facilities for local selective 

 ev.unin.aiioii hy r. ason ot the fact of its having a disc of 

 appn (i.ilde di.im.;. r, .iiid furnishing abundance of light. 

 \\ lien the problem is extended to the case of stellar atmo- 

 s|)her. s the difficulties are at once greatly increased. 



It was to afford the means of attacking this question in 

 an elTicient manner that Dr. Hale planned the installation 

 of a very high dispersion spectrograph to be used with the 

 new reflecting telescope of 60 inches aperture which has 

 lieeii so pri e;!y il s-nd. constructed, and adjusted into 

 working trim by Piof. G. W. Ritchey. With the new 

 spectrograph, the spectra of several of the brighter stars 

 have been successfully photographed, and from a pre- 

 liminary study of those of a Canis Majoris (Sirius), o Canis 

 Minoris (Procyon), and a Bootis (.Arcturus), Mr. W. S. 

 .Adams has been enabled to come to some interesting con- 

 clusions respecting the conditions existing in the atmo- 

 spheres of these stars (Astrophys. Joiirn., vol. xx.xiii., p. 64, 

 iQii; Contributions from the Mount Wilson Solar 

 Observatory No. 50). 



By means of subsidiary mirrors, the equatorial reflector 

 is employed in the coude form, the light being reflected 

 down and through the hollow polar axis to the slit of the 

 spectrograph. The equivalent focal length of the combina- 

 tion of mirrors is 150 feet (45-7 metres), giving an np 



ratio of 1 : 30. 



For convenience of manipulation and constan. 

 temper.ature, the spectrograph w.is arranged vertically 

 downwards in an underground pil. The spectrograph is 

 of the Littrow or auto-collimation type, consisting of a 

 lens of 15-2 cm. aperture and 55 metres focal length, used 

 in conjunction with a dense flint-glass prism of 63" angle, 

 and a plane mirror to send the light back through the 

 prism, thus giving the equivalent dispersion of two prisms. 

 The Lnrge scale of the dispersion thus provided will be 

 evident from the approximate linear equivalents, given as 

 follows : 



At X 4300, I mm. on photographic plate = I -4 A. 

 ,, 5000, ,, ,, ,, ,, =24 A. 



.1 6500, ., „ ,, ,, =6-2 A. 



