58 Spirit of Philosophical Discovery. 
Measurements of the Heat of the Surfaces 
of incandescent Bodies may, according to the 
experiments of M. Pouillet, detailed in the 
Jour. de Pharm., be thus obtained ; a very 
accurate thermometer is to be enclosed in 
a mass of ice, except a circular hole, for 
exposing the bulb to the radiant heat in- 
tended to be measured; such hole to be 
in form of a frustum of a cone, whose side 
continued would just circumscribe the hot 
surface to be measured: in which case, the 
thermometer will, by the inverse duplicate 
ratio of the distances of that and a stand- 
ard radiant surface, indicate the heat of the 
radiant surface under experiment. In this 
manner the heat of the sun’s surface is stated, 
by M. Pouillet, at 2552° of Farenheit : 
being 4° more than experiments by other 
methods give, for the heat of melting cop- 
per: the fuzing heat of iron being 34799. 
Why scratched Surfaces discharge more 
Heat by Radiation than smooth and polished 
ones, has been the subject of an inquiry by 
the Rev. Wm. Ritchie, in Jameson’s Edin. 
Phil. Journ. No. 23; whose conclusions 
are, that the considerably increased radia- 
tion from a striated surface is not caused 
by the mere increase of surface, but by the 
heat flowing and reflected from the sides 
of the furrows. The heat, radiated from 
the surface of a hemisphere, in lines per- 
pendicular to the plane of its great circle, 
he found, both theoretically and by experi- 
ment, to equal in quantity the heat, which 
the great circle would radiate in the same 
direction, if equally heated. 
Three Meteoric Masses, viz. a mass of 
iron, which fell Jong ago, and was noticed 
in 1809, at Brahin, in Rziezyca, Minsk 
District, in Poland; a stone, which fell at 
Zaborzyca, in Volhinie, on the 30th of 
March 1818; and another stone, which 
fell at Lerna, near the mouth of the 
Dwina River, in Poland, on the 30th of 
June 1820; these, perhaps, exfoliated frag- 
ments from terrestrial satellitula, which yet 
revolve, have been carefully analyzed by 
M. Lauzier (the results of which are re- 
corded in Brande’s Jour. No. 36), who 
found in each Nickel and Chromium, and 
the other usual ingredients of these extra 
mundane substances. 
General Charts of the Globe, shewing the 
Magnetic Meridians in every putt, have 
lately been constructed by M. Morlet, who 
has bestowed great pains to ascertain the 
route of the magnetic equator, or curve 
of variation of the magnetic compass, as 
traced on the terrestrial globe. 
western coast of Africa, in about 12° of 
east longitude from Greenwich, he has 
ascertained, that the terrestrial equator is 
now crossed by the magnetic equator ; pro- 
ceeding from whence towards the west, it 
descends to the,southward, and continues 
to recede, until it reaches 14° 10/ of south 
latitude, and there haying, in about 26° 
On the-_ 
[Feb. I, 
west longitude, attained one of its southern 
maxima, it then again rises gradually to- 
wards the equator, whilst crossing América, 
to the 98° of west longitude, at about 100 
leagues to the west of Gallapagos, in the 
Great Ocean. There it is again found 
very near to the equator, but its curvature 
changing, it does not cross the same, but 
proceeds almost parallel to the equator, at 
a maximum distance therefrom, in about 
118° of west longitude ; after which it de- 
scends again towards the south, until it 
reaches the second southern marimum, in 
about 3° 13/ south latitude, and about 162° 
of west longitude, on a meridian nearly 
intermediate between the archipelago of 
the Friendly Islands and that of the -So- 
ciety Islands. From hence it rises slowly 
northward, and cuts the terrestrial equator, 
in 176° east longitude, not far from the 
meridian of the Mulgraye Islands: then 
continuing its course to the north, it reaches 
its first mavimwm of north latitude, in the 
meridian of the Philippines, when it has 
8° 57 of north latitude; henee it reas- 
cends a little towards the equator, and 
reaches a minimum, in about 110° of east 
longitude, and 7° 44/ of north latitude, at 
the entrance of the Gulph of Siam, a little 
to the south of the Isle of Condor. It 
afterwards rises again northward, crosses 
the Bay of Bengal, cuts the southern point 
of India, and rising to 11° 47 N. lat. at- 
tains its second N. maximum at 60° E-long., 
in the Sea of Arabia: hence descending 
again towards the equator, it arrives at the 
eastern coast of Africa, which it cuts a little 
above the Straits of Babelmandel, and, cress- 
ing the interior of this continent, it arrives 
on the equator, at the point on the western 
coast, where our description began. The 
care and exactness with which this com- 
plex curve of the magnetic equator has 
now been experimentally traced, will, it 
is hoped, enable mathematicians to verify 
or correct their assumptions as to the 
number, the situations, and the relative 
intensities of the magnetic poles of our 
planet. 
That the Waves of the Bay of Biscay are 
of far less magnitude than those of the Ger- 
man Sea, has been shewn by Mr. A. Mac- 
donald, who, during the severe gales of 
October last, observed the waves to break 
against the Bell- Rock Light-house, situated 
off the. mouth of the Forth, in Scotland, at 
the height of ninety feet above the rock! 
whereas, in the Bay of Biseay, the Corduan 
Light-house, also on a sunken rock, off the 
mouth of the Garonne, whose parapet wall 
rises only thirty feet above the rock, is 
rarely and but very slightly overtopped by 
the spray or broken waves of this much- 
dreaded bay. in 
Framed Masts, in portable pieces, are now 
in preparation in Portsmouth dock-yard, 
on Sir R. Sepping’s plan, such as can be 
carried out, for the replacing of damaged 
PN or 
