318 



BELLACO ROCKS — REFRACTION. 



Jan. 



At low-water there are but eight feet on this rock, which is not 

 far from mid-channel, just without the entrance. 



We anchored near Watchman Cape, and in other places 

 along the coast, before reaching Port San Julian, and some 

 time was devoted to an examination of the Bellaco Rock and 

 its vicinity, as there is a dangerous reef extending from Watch- 

 man Cape towards, but not quite out to the Bellaco. 



In my own notes I find this rock mentioned as " almost 

 covered at times, but occasionally showing above water as high 

 as the hull of a ship !" In Mr. Stokes's journal, left with me, 

 it is mentioned in these words : " Passed between the Bellaco 

 Rocks, close to the eastern one, nearly a-wash and in the 

 diary of the Nodales"* voyage (in 1619), it is spoken of as " una 

 baxa que lababa la mar en ella," which means, a rock a-wash. 

 The rise of tide there is about twenty feet, which explains 

 the various appearances it had to my eye ; for at high water I 

 saw it almost covered, or a-wash ; and as the Nodales described 

 it similarly in 1619, there can have been extremely little, if any, 

 change in the relative heights of sea and land in this place 

 during the last two hundred and fifteen years.* Some time ago I 

 thought differently, having formed a hasty opinion upon the 

 fact of my having seen the rock as high out of water as a ship's 

 hull. I did not then consider how much the tide falls, nor did 

 I recollect, till I referred to notes, that I had also seen it 

 a-wash (the top almost level with the water), at times during 

 the many days we were in the neighbourhood. 



On the day that Mr. Stokes and myself made our respective 

 notes on the Bellaco (without any communication of opinion), 

 an extraordinary effect of refraction was remarked. The meri- 

 dian altitude of the sun (then far south) observed at opposite 

 horizons, differed no less than sixteen miles ! Similar effects 

 had been noticed before, especially on the Patagonian coast, 

 therefore we generally observed both ways; but to nearly 



* As the larger and eastern rock is about a hundred yards long- and 

 eighty wide, with kelp growing on most parts of it, I do not think the 

 top can wear away while so protected by sea-weed. 



