May 1 8, 191 1] 



NATURE 



)95 



the significant fact that the accelerated knots were com- 

 posed, to the extent of 75 per cent, of gases, not of solid 

 particles, and that, therefore, molecules not only could be, 

 but actually were, repelled by the action of the sun — con- 

 trary to current theory. The Royal Astronomical Society. 

 — Series of photographs of nebulae taken by Prof. G. W. 

 Ritdiey with the 60-inch reflector of the .Mount \\'ilson 

 Observatory, California, in 1910. Mr. A. Fowler, F.R.S. 

 — Spectrum photographs showing the composition of the 

 tails of comets. The spectra of the tails of comets exhibit 

 a number of double bands, which the photographs prove 

 to be identical with bands obtained from vacuum tubes 

 'ontaining carbon monoxide at a pressure of about 

 lOi mtn. An additional band, due to nitrogen, was pre- 

 -••nt in conii t -Morehouse. Solar Physics Observatory, 

 •^oiitli Kciisin^ttiii. — (i) Spectroheliograms of the sun. 

 Obtained on Friday, April 28, 191 1, about six hours before 

 the time of total eclipse at Vavau, and on Saturday, 

 April 29. Composite pictures are shown of the j)romin- 

 ences on the limb and the flocculi on the disc, taken in 

 K^K, (calcium) light. (2) Diagrams illustrating the 

 soathern hemisphere surface air circulation, (i) Scheme 

 of general suggested circulation, (ii) Curves showing lime 

 difference of pressure changes. (3) Observatioiw of 

 Halley's comet at I*"ostenl()\vii, Caterham. (i) 'I hi' i- m- 

 porary obser\'atory showing the tliree instrunnMiis u^- d : 

 9-inch Ih'iir\ pri-inatic camera, 10 feet focus, with om- 

 prism of 45" ang!.' ; 2-inch quartz calcite prismatic canicr.i, 



18 UHil' 



Dallin-v. 



with one prism of 30" a 

 raniera, 4 feet focus, (ii) 



inch 



Spectrum, 

 laborator\' 



vanadium. 



IOCll>, 



doublet camera, 4 feet focus, (ii) Plau- slu 

 and double nucleus of comet, drawing of visual 

 and photographic spectrum. (4) Pliotographic 

 spectra. Showing the flutings of titanium, 

 and chromium, employed in the reduction of 

 till' >|)i'c1i-a of Antarian stars a Orionis, o Ci.'ti, a Scor- 

 pionis, X:r. 



Prof. A'. If. Wood (Joliiis Iluplcins I'liivcrsity, Balti- 

 nunc). — (i) l''luorescence and resonancf spcctriun of iodine 



l)(>vfU>pnii-nt of 

 f.ii'hl from a 



vapour, with 

 band speclrm 

 mr>rcur\ a: 



hi-'hlv '■-:'• 



scpai-aieh' I>\ 



Innn, :,<u\ ill, 



po^.d 



hcliuu 

 from 

 all ih. 



friM,, 



monochromatic excitation. 



1 !i\ prr-seiicc of helium. 



-^ ■'] a1 lli'> ccnf ]--■ of ;i 



i ('<i)ilaining a small 



■ li >!i(>\\x brilliant fluoj-i 



• .\ -. resonance spectra ex( 



;.;i'eeii mercury lines, which 



inier])f>sin<^ attsorbing sere, 



''iill). In a lailli containin 



; iiiin. i)res^iire, 1 



la I 



■n- 



;l;iss bulb, 

 of iodine. 



;inf1 llie 



llle Iwo 

 • ul,-.erve,l 



in< 



ami 



ille 1, 



nnl 



■i-'ei rum. 

 ■llv eff. 



S\'s|e,l| 



helium 

 in llii' 

 liifh 



\ciled in the 

 pectrum of i(i( 

 •|l)e eo!Ii-i.,ii 

 ■f a transfer of . 

 n the iodini- moler 

 il 10 mm. the h.aiid 

 ■' ioilini- wapo 



neletle (liffr, 



■ i knowai litv 

 uiiorimdum. I'si 

 ,i)erimenial deier 



le vliper- 



with ill' 



rl f. 



ih. 



nil lU'- 

 a-pen, 



liaim 111 



u I a I 



prii 



•lal! 



ripliv 

 I'ariou 



The presence of small percentages of gas is immediately 

 indicated 1)\ ih.- appearance of an orange-coloured cap of 

 the same eharacier as appears when a wire, charged with 

 soda, is introduced into a Bunsen gas flame. (2) A 

 differential hygroscope (Sir Henry Cunynghame). The 

 device consists of two thermometers, one with a wet and 

 tlie other with a dry bulb. Instead, however, of being 

 placed apart as usual, the stems of the two are brought 

 into juxtaposition. They are not equally divided, but are 

 so arranged and divided that when the top of the column 

 of oil. <>f ilvin -ink- below the top of the column of the 

 other, an\ d.-ired h\grometric state of the air is at once 

 seen by simple inspection without anv -cale or refer. ■11.' 

 to any tabla, and irrespective of th.. 1. mp rauir. . 



Messrs. Elliott «Brothcrs. — The Aiisciun/ ;4\ ro-eomp 1 ■--. 

 .\ practical aj)plication of a gyrostat a- a niariivr'- •'"■'; 

 pass. The apparatus consists of a g\rosiai -o -.n^p.n.i. i 

 that its axis points to the true north, tlni- avoiding the 

 necessitv of any considerations of magn. lie variation. 

 The *' (iirective force" is considerable, and 'on th;\t accounr 

 the apparaui> can be made use of to transmit its indii .liion- 

 to v.ariou.- points in ;i ship. Mr. A. Mallock, F.R.S. — 

 Model of .a ■• detached escapement " for pendulum clocks. 

 The p.iulaknu is fri.e, in ili.- -ense that diuang the swing 

 ii maizes no intermiii.-iu contact- with .in\ -olid. \. c- 

 ili.. end of each swing an eleciric coiiiaci :~ m el ■ 'e ' 

 fine wire dipping in a m.rcury cup. 1 li. 



I established pas-..- ihroueli the coil- of an 



' which, bv m.-.an- of a " reinontoir " workiii:.; a ;.-cipio- 

 c.ating l.v.-r. can,-.-- a v.r\ weak spring to ,act so as to 



I maintain th.- o-cill,itioii. Consi.anT den-it\ in ili.- ;n:- 



I surrounding tlie pendukmi is appro\imai.l\ -.■eui 

 covc.ring hell gla>-, the edg.> of which dip- in :■■ 

 narrow annular canal partly filled with in.ri 

 alteration of 1 inch in tln' height of the liaroin. 

 the d.ai-il\ of til., eiiclo-ed air l>v ahoui on-- p e • 

 thousanil. ."^/r ir/7//(n/( h'amsny. /\. ('./.'.. /•./>'.>.. ."; / 

 Dr. h'. ir. (ii<iy. \ micro-halanca fe,;- !.al.,e. ■ ■'•'>''■ 

 e-s.-nlialh from 'th.. d.'-ign- of Me.'l.- a.nd (.r.m:, 

 about- i,jo,ooolh of .1 milligr.am. It i- (ompar.c 

 sen-ili\-.-. on., a; k i;i v.T-it \ ColL-g.- I...ing nior.- ibaii v ,■. 

 time- a- -..n-iiix.'. Ml.- plan of ad.bnL^ -mall wei^lii wa- 

 work.'d out at I niv.r-ii v C .' 

 tlv .apparent w.i-hl ot th.' 



sii-p..n<li.d from on.- arm b\' a -:e. ,. : . ^, •- 



pre--nr.- of air in the balanc.--c.-i-.-. It wa- with a babutc- 

 ,,f ihi- l\p.- that til.- d.-n-il\- of niloii wa- d- : - 1 nr ii'-.l '.> ' ' 

 I,.;, than on.--i.ntli of .1 culiic mill;-! 

 M.inlrv. .\nal\li. il bal.iiir.- with l)re 

 .>mplel.l\ 

 d-- of me 

 ,a-.. i^.ilealh th.- ea--- il. . 



attached to the paii-io 

 b,d'll.--plal.-s int.-rc-pl .an. I e ■ 

 .1-, .-11. ling from ill.- . - ■ 

 :|i, a> fean -Irikini: tl'- 



[di-p, 



met; 

 of 



h.. d 



i-p.-r- 



b.-:im ol ibi- ' 



inn. r c.a-.-. v'. . 



plat.-^la- -im 



batll.- -plal.-- ,1 



poim.-r. 111.--- 



\-.-cl i.m cm r. ni - .1-. 'iwii 1 



.-ind -o pr.-\ ■''■'• ■ M. le I ; 



c.»mbin.-d i\.\' 



\yio- ol il'.- 



ni'-.a-uriiie small ihickn. 

 \,v Ml. I-:. II. K.a\ — 



of m. a -III 111^ ill.- 

 77;,- \,ili.<n,i! /'.' 

 m.-i. r f..r i.-ii 

 o-xliihil.-.l \<^ 1 

 Mr. MUrd W. r ..' . 

 of w-ire- .-md pip. -. \ 

 . laclor (bk- 

 .w boi !- 



u\\: lorm 

 max 1. 

 . \ -b 



s. W 



! o I ^ ■ ' 

 and . 

 shad. 

 and 



IS.nfef! 



86' 



