I 427 ) 



2. ArnnK/i'inc)// i>l' the i)l)srrv(il)(nis. On this siibjoct 1 li;i\'o said 

 ;i I'ew words in tlu' i>n|»<M' inciilioiKMl. Here 1 shall coiisiih'r sonu» 

 points more in (h'lail. 



AH ni\- ol)S(M'valions were made l)v ihc method of ('(jiial aUitndos 

 of the moon and a stai'. Uecanse ol' tiio small latilnde of my station 

 {(f^ — 5'J2^) I could make the observations in such positions that 

 the parallel \n as at small anjj;les with the vertical cii'cl(\ i. e. that 

 the ])arallactic anule dillered litlh^ from IK)^ or 270''. Hence the ang'les 

 of the moon's orbit with the xertical circde wen» not «••reat eithei' 

 and thei-efore the accui'acy that can be reached by means of obser- 

 vations of the moon was m'tnally attained very nearlj', in so far as 

 it de[>en(ls on the u'eometi-ical conditions. 



1 nsed mv nni\ersal instiMiment described before, and the obser- 

 vations consisted in notinu' do\vn the inomcMits at \vhich the 

 visible limb of the moon and the com[)arison stai' attained the same 

 altitude. The instants of transit ov(M' the horizontal threads were 

 determined, tirst for the one, then for the otluM- object, either com- 

 bined with readings of the alidade-level. In this way I have obtained 

 24 observations of the \^^ limb scattered over 10 Jiigiits and 12 

 observations of the 2' liml) ovei' 3 nights. 1 regi'et that it has not 

 been [)Ossible to add to the last inimber. 



The instrument has always been nsed in the same [)osilio]i, telescope 

 right. In order to pi'epare myself for the observations! beforehand 

 computed for gi\en moments the azimuth and the zenith-distajice of 

 the moon and the stai-, while the azimuth of the instrument was 

 kjiowii by means of the hai'bour-light S. Kach time the level was 

 read just before the transit observations. The reticule has remained 

 in the same position since February J90I '), so that each time the 

 transits could be obsei'Ncd o\'ei' 7 threads. 



The «listances betwecMi these threads ^vere about 7^ (^, 4^ 4\ 7% 

 ()^ and owing to the i-apid succession of the ti-ausits and the rather 

 small powei' of the telesco])e. I did Jiol succ(M'd in estimating further 

 than the full beats of the chronometei". In future obscM-vat ions ir may 

 perha|)s be better to sacrifice some transits in oi-der to ti-y to reach 

 a higher degi'ee of accuracy in the othei'S. 



Anothei' result of the ra|)id succession of the sej)arate transits was 

 that 1 was unable to follo\v the observed object in azimuth during 

 its transit o\-er the reticule. Hence in some cases it passed in 

 a somewhat obli()ue dir(M'lion and while I always took care that the 



1) Comp. Gonlribiilions to llio (tetoi-iaiiiation of geograpljiral pusilions etc. I. 

 p. 3 (276). 



~) Ibid. p. 16 (289). 



