36 



C. V. L. Charlier 



The most extensive photograph of this part of the heaven known to me is 

 that of Batley pubhshed in H. A. LX. It is made with the celebrated Cook lens 

 of the Harvard Observatory, having an aperture of only 1-iuch. It is one of the 

 instrument used in making the Harvard map of the sky. The exposvu'e lasted for 

 24 hours, distributed over four nights. Bailey estimates the hmits of the chart to 

 be in a 17'' to beyond 19'' and in o — 10" to — 50". The constants for the plate 

 of Bailey was, at my request, kindly determined by Docent Gyllenbekg. Using 

 a method of reduction of photographic plates, elaborated by Gyllenberg, which 

 method is to be reproduced in the 3Ieddelanden, the plate coordinates were computed 

 for all globular clusters in table 2, which would be found within the plate. These 

 clusters are indicated on plate VII, which gives a reproduction of the plate of 

 Bailey, by a red cross. 



The distribution of the globulars on the plate is very singular and even sur- 

 prising. Before performing the computations I had supposed that »these globular 

 clusters seem to avoid the regions of greatest brilliancy* as is said by Bailey (1. c). 

 We find, however, that quite the contrary takes place. The globulars are to be 

 found just in these brilliant regions and are separated into two distinct parts by 

 the dark lanes and holes to the right of the plate. The path of the XZ- plane of 

 the Galaxy is furthermore not coincident with the great star cloud hut falls just along 

 the dark lane. 



The rôle of the dark lane is in this case evident. It is nothing but a dark 

 nebula hiding for us the centre of the system of globular clusters and also hiding 

 the central part of the Milky Way, the exterior parts being visible on both sides 

 of the dai'k nebula. It had been possible to draw this conclusion already from the 

 chart of the apparent distribution given on plate IV, where the division of the 

 clusters into two parts separated by the Milky Way is, indeed, plainly shown. 



This interesting association of the Milky Way with the globular clusters gives 

 an important contribution to our knowledge of these singular bodies, though their 

 true nature still is hidden behind a seemingly impenetrable veil. 



21. In the table 5 are given a list of objects considered as globulars situated 

 in the Large Magellanic cloud. The columns have the same meaning as the corres- 

 ponding columns of table 2. Though the determination of the distance of the 

 Large Magellanic cloud from the diameters of the globulars must be very uncertain 

 (the globular character as well as the diameter of the objects being vaguely deter- 

 mined) I have applied even here the same method as regarding the globulars in 

 the galaxy. 



The mean value of the 16 globulars in the L. Magellanic cloud amounts to 

 I'm. Using a Scale equal to 1.7 we get a distance of 125 sir. = 0".ooi6), With 

 this value of r have the values of x', y', s in table 5 been computed. 



