EL KOXCADOn. 
203 
the climate of the neighhouriiig land; but it is less easy to 
conceive that those slight changes of temperature (for 
instance, a centesimal degree on the bank of La Yiboi’a), 
can impart a peculiar character to the atmosphei'C of the 
shoals. May not these submarine islands act upon the for- 
mation and accumulation of the vesicular vapours in some 
other way than by cooling the waters of the surface ? 
Quitting the bank of La Vibora, we passed between tlie 
Baxo Nuevo, and the light-house of Camboy; and on tin- 
“2nd March, we passed more than thirty leagues to west- 
ward of El Itoncador (The Snorer), a name which this shoal 
I'as received from the pilots, who assert, on the authority of 
'Weient traditions, that a sound like snoring is heard from 
•tfar. If such a sound be really lieavd, it arisQii. no doubt, 
irom a periodical issuing of air compressed by the waters in 
a rocky cavern. I have observed the same phenomenon on 
several coasts, for instance, on the promontories of Tenerifle, 
in the limestoire.s of the llavannah,* and in the granite of 
Bower Peru, between Truxillo and Lima. A project was 
formed at the Canary islands, for placing a machine at the 
issue of the compressed air, and allowing the sea to act 
«s an impelling force. While the autumnal equinox * is 
everywhere dreaded in the sea of the West Indies (except 
On the coast of Cumana and Caracas), the spring equinox 
produces no efiect on the tranquillity of those tropical 
*‘ogiona: a phenomenon almost the inverse of that observ- 
ahle in high latitudes. Since we bad quitted La Vibora, 
fhe Weather had been remarkably fine; the colour of the sea 
"(as indigo-blue, and sometimes violet, owing to the quan- 
f’ty of medusae and eggs of fish (purga de mar) which 
oovered it. Its surface was gently agitated. The thermometer 
^opt up, in the shade, from 26® to 27"; not a cloud arose on 
file horizon, although the wind was constantly north, or 
^•N.W. I know not whether to attribute to this wind, 
which cools the higher layers of the atmosphere, and thei'c 
produces icy crystals, the halos which were formed round 
fhe moon two nights successively. The halos were of small 
dimensions, 45° diameter. 1 never had an opportunity of 
**eeiug and measuring anyi" of which the diameter had at- 
* Called by tlie Spanish sailors “El Cordonazo de San Framasco. 
In Catitain Parry's first voyage, halos were iiicastired round tlie sun 
