122 



KNOWLEDGE. 



April, 1915. 



Saturn is an evening star in Gemini. Is now approaching 

 conjunction with the Sun. 2i° South of Mercury on 31st. 

 Polar semi-diameter 8". Major axis of ring 38", minor 17". 

 Angle P-6°-2. 



The Satellite positions are not given, owing to the planet's 

 proximity to the Sun. 



Uranus is a morning star, but badly placed. In 

 quadrature with Sun on Sth. Near Moon on 6th, 7 h m. 



Neptune is an evening star in Cancer; diameter 2". 



Double Stars and Clusters. — The tables of these, 

 given three years ago, are again available, and readers are 

 referred to the corresponding month of three years ago. 



Variable Stars. — Stars reaching their maxima in or near 

 May, 1915, are included. The lists in recent months may 

 also be consulted (see Table 23). 



Meteor Showers (from Mr. Denning's List) : 



The May Aquarids are of special interest from their asso- 

 ciation with Halley's Comet. Accurate observations of their 

 paths are desirable. 



Table 23. Long-period Variable Stars. 



Night Minima of Algol l d h -4m, 3 d 9 m -2e, 18 d 5 h -3m, 21 d 2 h • 1 111, 23 d ll h -9e, 26 d 8 h -7 c. Period 2 d 20 h 48 m -9. 

 Principal Minima of /3 Lyrae 5 d 9 h m, 18 d 7 h m, 31 d 5 h m. Period 12 d 21 h 47 m -5. 



Table 24. Occultations of Stars by the Moon visible at Greenwich. 



From New to Full disappearances occur at the Dark Limb, from Full to New reappearances. 



POLLARDS. 



The making of pollards ensures a supply from time to 

 time of long poles suitable for fencing and other purposes, 

 in much the same way as they are obtained in the under- 

 wood of copses. There is this advantage, however, about 

 the former method, that pollards can be grown in odd cor- 

 ners, along the sides of streams (as in the case of willows), 

 or in hedgerows. Where we find pollards in woods or 

 scattered about common land, it seems likely that 

 they were produced in connection with common rights, 

 and that they were cut legitimately or otherwise by 

 cottagers who were not supposed to touch the forest trees. 



There is no doubt but that old pollards which have been 

 left alone for many years, such as those at Burnham 

 Beeches, become very picturesque, but their conservation 

 is a matter of difficulty. The old trunk becomes hollow, 

 and often a mere shell has to support a large number 

 of solid branches (see Figure 93), each of wh'ch may 

 weigh several tons. Our illustrations (see Figures 93 

 to 97) show how, in the slightest wind or in the 

 still air, the pollards may break up, and many of them 

 have to be cut somewhat drastically in order to save 

 them at all. 



