ASTRONOMICAL MEMORANDA

W. C. W.
1881 Science  
has imnestigate(d the subject recenitlv, to retain these namles to (lesignaie the asexual and se'xual stages reslctively. These plaIntsbelong to the interestitng or(ler Saprokqpziazecra. Other speciecs of the saiime or(ler are abun(lant oi dead and( living tfish, cray-wfish. etc. They have somiietimiies p)rove(l very deStructixe totilhe you fislh inl hatcheries. TIh1e species of thie order are niot well known, althouglh examl)les are easily ol()htaicd. J. C. A. MICROSCOPY. Mr. Juli -n I)er)y
more » ... . Juli -n I)er)y recently read before the (Ouceett Microscoi,ical Clab a papcr d'Iscribing various slecial dodiges," which nmay b) mniploycd by microscopis'ts to facIlitate their rese irches. I. When allowing all but adepts in the use of microscope to peep through my hIigh power glasses, I have often felt a certain degitee of uineasiness, not to sav of alarm, regar(liti the fate of valuable test-sli(les, or still more valuable obj;ctives. Mlany otlhers here present have no doubt exl)erienced the saime (l:scomfort wvhiJh I findl an easy matter to attenuate to a conisid-lrable exteit, by focussing foml tilhe eyep)iCeC inSte;ad of fromll thle COarSe or the slow mnotion. All thit is nel'tded for this is a rack an(l pinion to the Ce\lpiCce ot CoISidiler:iblt' ltCrtlh .\ T inich or txo ul) or down correspl)n(ls here to a ftration of a turn of the linie adjustmltnt kf thie lic roscope, so th: lt very little (langer exists of' a'y sud4lden contact vith tile covering glass. As s )on as an indistinct view ot tlhe object is obtained through the ordinary coar1-se adjustn,rnt of tlh Iticrosco,)t b)dy, tlle f cus is brotught to V\act ilnsi 1hv mealns of It 1C ti St I )1t (of t he evePi .'e witlit much iliftiilty'c. F1 dIWmistivtiolts ror e\lkiibitiols ill public titictsiscoi s ve tillits I'v itIle.wt1 lwitit the ol dilu.lv tline Illtotiol. II. \V Illentitippig x ing w ith ii etroM jo', the ilitliculty of me1aIsulrling extctly the Ipowit it' fin;e litl(iS o' absorption buunds ts ottenl grI at, evewn I\itsin usi-tht .a(dmirable microimieters invented bv Mr. IBrow\nin-awd Mt. Srtlv). 1 lin(d that in milost prac.tical cases the mnicrosp)ectrum caui 1be throwsn upon Slhe-t of white pal)pr by neians of atn or(inarv camier luidL It.la placed over the eyepiece of thle S)CCtlt0c)pe. Sitro.g li' hit 1v mileas of a cond(letser hias to be thrown thlrough the 1(iqidiil un,lIr exaumination. ll meatns of an iv(rv ruIlt, filleIx (iVided, ain( brought backi to a know,vn linte, ;;av 1), all o;thert liltes or bands imay l)e ilirtetlCly mIIItCtirod off on tilh trile, and, if (desirecd, thl exact results in mililliontls o)f a 1tliUnittre nil-y then be comIputecd by any of the kniowti intrp, )a-tioIn formuke, sucth as are given in Suffolk's uistftil little book. Ill. h'l'e arrangement of snmall microscopic olbjects, sticth as diatomis, toraminiferla', tc., on slideds in regul;Ir litwc. citcles 01 pittetlis, call be itiluchfliilitateil itn tle follo\ing way I )raw wx'tlh a per ;and inik crss lites, or ciclt s, or any'ofl.r figurtt lrciiretflcd oit thle sktrfawe(d (lite ltiitn mirrot of tiet m icroscope ; tt 'n focitsdown titil tile imiage ot tlit-se lilne;S is setIt onl ilit ull)pr su rIack of thl tol) lenlts of thle condenistelr. B1 mleanls of a itecht nital ting r, or of a steady Itind wvitlh a rest, n') dlilcultx Nvill now be exp rienced in placing -the objj cts in pertfecty regrular or(ter. IV. I now obtain excellenit c nmdensed monocihront;atic liglht by meians of a bUll's cye of unuLsuSl external shape, the interil l portion of whlich, iowever, is tilled wvith glyceriiet or oil of cloves colored to suiit. Thiis ullls) e hasa plattc bick utd a cottcav"o-coivcx frmtt, and tlhe liq(tlidI is itrtodueed 1tll-htohg a hole inl tielti t sitic. e(l)S(ed by a SmIllill gollitt(l stopper. 'l'itis apparitlus is futiatsli(ed vi'It unixtsdti>,t llotiots, .l1(1 has a rack mnd ptiiliot, foot. \tx;vs madefort' itoeb' Mr.,1. Blritntiig, W liei usiog blue 1l ig;t. ptrtdue d > A i tv"auito i'I Stlptate Siduttoits, I have resolved, by mieans of thlis molltochroillattic bulls-I eve amphipleura, with objectives in my possession, which wt'ill hardly shoxiw PI irosjgma aigu/altatum unuler ordinary cotnclenser illumit aticn. =,-7',77", 7 _ = !7 V. 9Som11e timRe ag,o, Mr. J. E-. lngp-n, on1 mny behilf, imia(le a commizlunicationi to the Club) in regar(l to a growing regarCl to a growing slide I ha(d devise(d for some special researches I was followinig at the timiie. Some difficulty seems to have been foun(d in th-m;aking of tlwse slides, so that it is wvith I)leasure I nox offer a still more simple contrivance for cb)!aining the sante results. 1e-re is thl rLceip)t: Take ant ordinary glass slip \xith a circular lhole, say, half an inichi or more in (liameter in thle mlld.11e; lay this slil) on an ordinary, glass slide, not put;f rated. 1Then grease tile top of the tupper or perfor-ateI.1 S!(le' itist :l littlet \\x.y arounil the circitlar hole, and joinill tlltz 1\\v) SuitS Of g.1usS 1)b' ImeanS Of tWo tubl!ier titigs se Fig.) . 'I'll o'iject is then l lict(l Oil a tiliti cover--liss. soaewxhat lait-r thalni the hole in the sli1e: it is c vtred( h! a tlitin -gass cover, '.in. in (limetert the xvhdl! is tilhn turned (lxvn and(l fastened to the slide by tiet dfi-brence \\v.tlt the grease, vlile tlte sm.all cover p)recut the lt itingini, of tlw liquaidl. '[hte pl1nt or aniiiial tinIer Vi t X t1 1 o fliuto hilds it self c Infit(l i:t a sort of Ilintti(re '
doi:10.1126/science.os-2.34.70-a pmid:17789389 fatcat:kgkkq4q6pjb7rnb3qfw2jqixpq