' Dr. Fothergill’s account of ice islands. 8} 
POSTSCRIPT. 
SINCE writing the above, on being admonished that part of my 
paper had been anticip:ted by M. Peron, I hastened to peruse his me- 
_ moir,* which had till now escaped my knowledge, or I should cer- 
tamly have noticed it. Much credit indeed is due to M. Peron’s 
assiduity in marking the temperature of the ocean four times a day ; 
but his assertion, that its temperature increases in approaching conti- 
nents or islands, is diametrically opposite to what I-have observed, 
and also to the experiments of Dr. Franklin and some of the ablest 
English navigators. They had long before, with es care and ac- 
curacy, explored the ocean to a far § preater. depth than M oe 
discovered the increasing cold even t to Pde" fens pom of salt 
water. But what. is Pasquier. neither they nor M. Peron have from 
thence attempted to explain the formation of ice islands in temperate 
climates, or their final cause, or, what is of much greater importance, 
the best method of guarding vessels against their terrible effects, or 
of pointing out their appenye) ia dat nigh: ae the peg pe ~ 
as. s highly oetiable, I find matenied in ™M. Pens s ‘memoir, , that 1 was 
not discovered long before by the authors I hl? mentioned, and on 
whose accuracy I have Sones see Adoy dation of 
have ventured to advance. In which it ; 
of my being anticipated by 5% he has been anticipated. by them ; ; 
of which, however, this learned society, to whom I have the honor 
to addres it, will judge. Should it be deemed unsuitable to their 
designs in their ensuing volume, they will PsN to rope "eg nclosec 
to the care of Mr. John Warder, Race st ae iladelphiaa 
PCR a Ny m ll : Speed ieee Hi 
