made in the Coquille by M. Duperrey. | 285 
termine whether these p oints belonged to the magnetic equator 
or the terrestrial equator. The second supposition could hardly 
bereconciled with the existence ofa diurnal variation of from three 
to fourminutes at Rawack: for this port, situated in the country 
of the Papous, is only in 0° 1'4 south latitude. Nevertheless 
it seemed desireable, in order to dissipate all uncertainty, that 
the pheenomenon should be observed between the two equators. 
Such was the principal object of the stay of M. Duperrey at 
Payta. In this city, situated to the north of the magnetic 
equator and to the south of the terrestrial equator, the 
northern extremity of the needle observed with a microscope 
moved, as in Europe, from east to west, from eight o’clock in 
the morning till.noon. ‘This angular deviation is very small; 
but its direction, respecting which the observations leave no un- 
certainty, would seem to authorise the conclusion, that all 
along the magnetic equator the horizontal needle is not sub- 
ject to diurnal variations. In other stations situated like 
Payta,—at the Isle of Ascension, for example,—we have never- 
theless been abie to see that this inference would have been 
premature. The phznomenon is more complex than would be 
imagined. Perhaps the changes in the declination of the sun, 
which in Europe occasion such great variations in the extent 
of the diurnal oscillations, produce, according to the seasons 
under the tropics, motions of the needle in an inverse direction. 
Further observations made in months and places suitably 
chosen will remove these doubts. It appears to us also, that 
it would be very useful for the Acadeiny, from this time, to 
recommend this inquiry in a particular manner to the attention 
of navigators, especially if, as is announced, a new expedition 
for discovery is soon to sail from our ports. 
To terminate this article, the length of which we hope will 
be excused, we have yet to add that M. Duperrey has given 
all his attention to the experiments from which may be de- 
duced the comparative intensities of terrestrial magnetism in 
various places, and that he is also engaged in making obser- 
vations proper for giving the corrections of which the mag- 
netic elements obtained at sea are susceptible. It has ap- 
peared to us that in general these corrections will be very in- 
considerable. 
Meteorology. 
Meteorology will have been enriched by the expedition of 
the Coquille, from a journal in which, for thirty-one months in 
succession and without there being one exception, were noted 
six times a day the state of the atmosphere, its temperature, 
its pressure, and the temperature of the sea. While lying-to 
for example, at Payta; at Waigiou, under the terrestrial equa- 
tor ; 
