OF ARTS AND SCIENCES. 



83 



minimum adopted by Schonfeld. A negative sign denotes that the 

 time precedes the minimum ; a positive, that it follows it. 



The elliptical orbits B and are much smaller than the others. 

 Since the eclipse takes place near the peri-astron, the angular motion 

 is so great that the radius vector must be reduced to maintain the 

 same duration of eclipse. 



To give a more tangible idea of the dimensions of this system a 

 projection is given of the orbit denoted by D in its own plane in Fig. 1, 



TT sen TjT 



Fig. 1. 



Fig. 2. 



and as seen from the Earth in Fig. 2. In both projections A denotes 

 the primary, B the satellite at first contact, C when half across the 

 disk, D at the last contact, and E and F at its elongations. The 

 scale is one hundredth of a second to a centimeter. Accordingly, if 

 Fig. 2 is removed to a distance of 206 kilometers, or about 120 miles, 

 it would appear of the same size as Algol when seen from the Earth. 



The application of the spectroscope to this binary star oflers a most 

 interesting field for work. Assuming the same data as before, we find 

 the circumference of the orbit equals 2 tt X 0".0138 = 0".087 ; or 



VOL. XVI. (n. S. VIII.) 3 



