183^. QUARANTINE — -SWELL SQUALL. 49 



regulation was adopted on account of the reports which had 

 reached them respecting the cholera in England. 



Observations on shore being indispensable for our purpose, 

 and finding, after some discussion, that there was no chance of 

 attaining our object in a manner that would at all compensate 

 for the delay caused by anchoring and performing quarantine, 

 we weighed without further loss of time, and made sail for the 

 Cape Verd Islands. 



This was a great disappointment to Mr. Darwin, who had 

 cherished a hope of visiting the Peak. To see it — to anchor 

 and be on the point of landing, yet be obliged to turn away 

 without the slightest prospect of beholding Teneriffe again — 

 was indeed to him a real calamity. 



During the whole of the 7th, the Peak was visible ; but on 

 the following day no land was in sight, and we made rapid 

 progress. A very long swell from the north-west, which we 

 felt until the 10th, was probably caused by a gale in the nor- 

 thern Atlantic ; and, judging from its size and velocity, I 

 should think that it could not have subsided before traversing 

 many, perhaps ten more, degrees of latitude ; which would be 

 to about 10° north. It is interesting to notice how far the 

 undulatory movement of water reaches : in this case it ex- 

 tended through at least ten degrees of latitude where the wind 

 was from different quarters, and probably much farther. 



An unusual appearance was observed on the 12th. A cloud 

 like a dense fog-bank approached ; and as it drew near, the 

 lower and darker part became arched, and rose rapidly, while 

 under it was a white glare, which looked very suspicious. 

 Sail was immediately reduced — we expected a violent squall ; 

 but the cloud dispersed suddenly, and only a common fresh 

 breeze came from the foreboding quarter. Neither the sympie- 

 someter nor the barometer had altered at all ; but the cloud 

 was so threatening that I put no trust in their indications, not 

 being then so firm a behever in their prophetic movements as 

 I am at present. Nevertheless, I would by no means advocate 

 the neglect of any precaution suggested by appearances of the 



VOL. II. E 



