( 122 ) 



If in these formulae we substitute lo<j q sin I = 9.5488 ( — ) , 

 %() co^- / = 9.9707' (+); ;. = 55°26'95 and add to the obtamed 

 time^ the adopted loiigitude of the battery 3''41m48^1, tlie error of 

 which does probabl}^ not exceed one second, as appears from the 

 preceding investigation, we obtain the following results. 



Con- 

 tact 



M. T. Greenw, 

 com p. 



M. T. St. Denis 

 comp. 



Obs. 0. 



S, 



Obs -Comp. 



0. I s. 



I 



II 



III 



IV 



•131i5r)m5r)S.O 

 U 26 -19, 3 

 17 .58 43. 5 

 48 28 23, 4 



17h37m43f^,1 I 17ii39m50s: 



■18 8 7 ,4 missed 



21 40 31 ,6 I 21 39 16,2 17-,6 



22 10 11,5 I 22 9 9,7 I 12,5 



_j_imI7s 



— 1 15,4 

 —1 1 ,8 



_liul4s,0 

 — 59,0 



Neither Mr. Soeters who observed with the telescope ofthehelio- 

 meter, noi' myself who used the Fraunhofer telescope of Mr. de 

 Beaueort ^) have seen anything of the so-called black drop. The 

 former telescope was provided with the strongest eyepiece, magnifying 

 86 times, the latter with one magnifying 121,5 times. 



I shall say only a few words here on the observations with the 

 heliometer and the photoheliograph. 



The heliometer made by Merz at Municii has caused me through 

 its numerous imperfections much trouble and numerous investiga- 

 tions relative to the instrument proxed later to be valueless. Only 

 a few days before the transit took place we detected a defect in 

 the construction of the instrument, which rendered the adjustment of 

 the parallactic stand illusory, so that all the measured position angles 

 were- unreliable. Nevertheless I have made complete sets of obser- 

 vations with the heliometer, viz. distances of the "Perseus-stars", for the 

 determination of the scale value and during the transit two sets of 

 eight distances between the limbs of Venus and of the sun. This was as 

 much as the cloudy state of the atmosphere prevailing during the whole 

 transit would allow to do. The first set was made in the ordinary 

 manner, the other along the most advantageous chord. (Versl. en 

 Meded. Kon. Ahid. Amsterdam, Nat. A f d. 2' Reeks, Vol. lX,\).lTi). 



The division errors of the scales must still be determined ; I hope 

 to do tills soon and then to revert to these measurements. 



As to the observations with the photoheliograph, unfortunately the 

 atmosjihere, even in the moments that it allowed measurements with 

 the heliometer, had a very bad effect on the clichés made. The 



1) In my previous paper 1 have erroneously mentioned Mr. Stoop as the owner 

 of this telescope ; he possessed it in 1835, wlien Kaiser used it for his observations 

 of the comet Halley. 



