THE TIDES 313 



To-day (Aug. 25, 1882), a committee, consisting of only 

 two members, Mr. George Darwin and Professor Adams 

 of Cambridge, have been appointed, and one of their chief 

 objects will be to examine the long period tides. 



There is one very interesting point I said I would endeav- 

 our to speak of if I had time; I have not time, but still I 

 must speak of it the influence of the moon on the weather. 

 " We almost laugh when we hear of the influence of the 

 moon on the weather," Sir F. Evans said to me, " but there 

 is an influence." Gales of wind are remarkably prevalent 

 in Torres Straits and the neighbourhood about the time of 

 new and full moon. This was noticed by Dr. Rattray, a 

 surgeon in the navy, in connection with observations made 

 by the surveying ship, Fly, during the three years 1841-44. 

 Dr. Rattray noticed that at those times there was a large 

 area of coral reef uncovered at the very low water of the 

 spring tides, extending out some sixty or seventy miles from 

 land. This large area becomes highly heated, and the great 

 heating of that large portion of land gives rise to a tend- 

 ency to gales at the full and change, that is at the new and 

 full moon. This indirect effect of the moon upon the weather 

 through the tides is exceedingly interesting; but it does not 

 at all invalidate the scientific conclusion that there is no 

 direct influence, and the general effect of the moon on the 

 weather the changes in the moon and the changes in the 

 weather, and their supposed connection remains a mere 

 chimaera. 



The subject of elastic tides in which the yielding of the 

 solid earth is taken into account is to be one of the primary 

 objects of Mr. G. Darwin's committee. The tide-generating 

 force which tends to pull the water to and from the moon, 

 tends to pull the earth also. Imagine the earth made of india- 

 rubber and pulled out to and from the moon. It will be 

 made prolate (Fie. 134). If the earth were of india-rubber 

 the tides would be nothing, the rise and fall of the water 

 relatively to the solid would be practically nil. If the earth 

 (as has long been a favourite hypothesis of geologists) had 

 a thin shell 20 or 30 miles thick with liquid inside, there 

 would be no such thing as tides of water rising and fall- 

 ing relatively to land, or sea-bottom. The earth's crust 



