164 On an Isothermal Oceanic Chart, illustrating 
cember, is probably two and a half degrees above the cold of the 
coldest month, judging from the relative temperatures of the lat- 
ter half of December and the month of February at San Blas. 
Leaving California, the isocryme of 68° will therfore bend a little 
southerly to Q240, j in longitude 115° west. In 23° 56/ north, 
128° 33’ west, Beechey, on January 11, found the temperature 
< the sea 67:83° F. The line of 68° passes north of the Sand- 
wich Islands. The mean temperature of the sea at Oahu in Feb- 
ruary, 1827, was 69°69° F. 
Near China, this isocryme is bent far south. At Macao, in 
winter, Vaillant found the sea-temperature, on January 4, 59° F.; 
on January 5 to 10, 52°7° to 50° F.; January 11, 12, 49'87° to 
48: 74°: PF .5 January 13 to 16, 50° 9° to 52-16° F.; and at Tou- . 
ranne in Cochin oes on February 6 to 24, the sea-temperatiire 
was 68° to 684° F.; in 16° 22’ north, 108° 11/ east, on January 
24, it was 67°; in 12° 16’ north, 109° 28’ east, it was 74:12° F. 
The very low Macao temperature is that of the surface of the 
Bay itself, due to the cold of the land, _ not probably, as the 
other observations show, of the sea outsi 
The line, before passing south, bends ieabenid to the south- 
east shore of Niphon, which is far warmer than the southeast 
coast, along Kinsiu. In the Report of the Morrison’s visit to 
Jeddo (Chinese Repository for 1837), a coral bottom is spoken of, 
as having been encountered in the rae of Jeddo. According 
to Siebold (Crust. Faun. Japon., p. ix.), the mean winter tempe!- 
ature (air) of Jeddo is 57° F.; while that of Nagasaki, although 
farther south, is sor F. 
Isocry of 62 ° F.—On January 8, 1827, Beechey found in 
29° 42’ north, 126° 37’ west, the temperature 62:75° F. ; while 
on the preceding eo 32° 42! north, 125° 43’ west, the sea-tem- 
perature was 60°5° F. Again, on December 11, in 29° north, 
120° west, the sebieuitshes was pee ae 
Isocryme of 56° F',—At Monterey, on January 1 to 5, the sea 
temperature according to Beechey was 56°; but the mean tem 
perature of the sea for November 1 to 17, was 54-91°. In the 
ellow Sea, the January ped meee is 50° to 56° F., and the 
line of 56° begins south of 
Tsocryme of 50° F.—At ceca panei se November 18 to 
Deceriiiel 5, 1826, Beechey found the mean sea-temperature t0 
be 61-149 F. , and off Monterey, in longitude 1235 west, the tem- 
perature was 50°75° F., on December 6. But in December of 
1826, the mean sea-temperature at San Francisco was 54°78? F-. ; 
and for November, 60°16° F. The line of 50° F. (mean “of the — 
coldest thirty consecutive days), probably leaves the coast at Cape 
Mendocino. 
Tsocrymes of 44° and 35° F.—Captain Wilkes found the tem- 
perature off the mouth of the Columbia River, satiate en de- 
