316 THE BINARY STARS. 



Fig. 3. — Ventral surface of nymph, showing the difference in the gen- 

 ital area at this stage, and at that of the imago. 



,, 4. — Dorsal surface of larva, drawn from a specimen hatched the 

 same day. 



,, 5. — Palpus of imago. 



,, 6. — Tarsi and unguis of larva, showing the pectinated hairs. 



,, 7. — Genital plates of 9 • 



,, 8. — Genital plates of ^. 



Zbc Binary Stars,'' 



By H. Wyles, L.D.S., Leeds. 



SCATTERED throughout space are numbers of stars which, 

 upon examination with the telescope, are seen to be double, 

 two stars being visible where to the unaided eye there only 

 appeared to be one. These double stars offer a great variety of 

 appearances to the observer, the two components in some cases 

 being widely separated and in others very close together, so that 

 their separation requires a telescope of great size and perfection. 

 Then, again, they are sometimes composed of two stars^. of the 

 same apparent degree of brightness or of the same colour, and 

 others appear of widely different magnitudes and of very different 

 colours. They have been most carefully observed by astronomers 

 for more than a hundred years, and they have yielded in return 

 results and information of the most important and interesting 

 nature. Who would have believed at one time that we should 

 ever be able to weigh a star and say what its mass might be when 

 compared with our own earth or with the sun ? Yet this is only 

 one of the results which assiduous observation of the binary stars 

 has enabled astronomers to achieve. 



The name of " binary " is only applied to those double stars in 

 which the two components have been shown to have a physical 

 connection with each other, and to form a pair which are really 

 very near together in comparison with the immense distance which 



*A paper read before the Leeds Astronomical Society March nth, 1896. 



