55 



caused by these engulfing processes form the spots, which we see so regularly 

 following the prolongation of the " radius vector" of Venus. Such ia M. Hoek's 

 theory of the Sun spots. 



Now here I may perhaps claim your courtesy for a very few words, on a 

 subject somewhat similar to this tidal action produced by Venus. I mean the 

 ordinary explanation (even by so recent an author as Guillemin, in his beauti- 

 fully illustrated work The Heavens), 'of the cause of the tides on the reverse 

 side of the earth, or that turned away from the moon. I have long been 

 convinced in my own mind that the ordinary explanation needs revision, and 

 before I read M. Hoek's letter, on that kindred subject, I had explained it to 

 myself thus : Matter, when free of motion as to its atoms, such as water, sand, 

 &c., has atendeney to range itself in a line in the direction of the strongest 

 attraction. Let ns apply this law to the case in point. The tide produced by 

 the moon (or sun in a less degree), on the obverse side of the earth, or that 

 immediately under the source of attraction, is manifestly in obedience to this 

 law. Why not so, on the other, or reverse side of our planet ? For, which 

 is the line of strongest attraction ? Surely that of the moon's " radius vector" 

 continued through the earth's centre, and prolonged onwards into space. As 

 a fact, the waters of tlie ocean by gravity seek that line, and it is this simple 

 agency which has escaped detection, in the olden theory of the tides. 



But I have now trespassed far too much upon your patience. It will 

 suffice, therefore, to say, in regard to the other subjects I named, that the 

 evidence is not yet quite complete as to the supposed alteration in form of the 

 Lunar Crater, "Linne." A partial obscuration of the latter, for a time, by a 

 "whitish cloudy patch" (for so speaks the R.A.S. report), would go far to 

 prove the existence of something at least of a lunar atmosphere. Time will 

 doubtless bring with it more evidence for future conclusions on this subject. 



The action of the tides, as affecting, in an infinitesimal degree, the 

 rotation of the earth, seems now accepted as a theory ; but (to quote the report 

 again,) "that the whole of the outstanding quantity of lunar acceleration is due 

 to this cause, is perhaps still an open question." 



It now remains for me to thank the members present of the Woolhope 

 Field Club for thus so patiently listening to a somewhat long, I trust not tedious, 

 digest of matters of present interest in astronomy. I venture to express a hope 

 that such and similar subjects of thought and discussion, akin and parallel to, 

 though not immediately identical with our ordinary special study, may not b^ 

 without their interest and advantage. 



Of one thing I am certain, that all such studies of the marvellous works 



of the Great Creator carry with them their own reward, and that of the many 



truths which touch the heart and mind, uttered by one who loved our lovely 



Wye (here close at hand), none is more true than that embodied in the noble 



poem of which our river is the special theme, that 



Naturft never rtid betray 

 Tlic heart that loved her. 



