Geographical Collections: 13] 
Some comparative observations made at sea, with the assistance of thermome- 
ters whose bulbs were black and white, will have so much the more interest, that 
Sir Edward Parry and Sir John Franklin occupied themselves near the Pole 
with similar researches ; and it has been thought, that from them it might be 
deduced, that solar radiation is the less powerful as we approach the equator. 
Natural philosophers will also learn with satisfaction, that our navigators have 
determined the temperature of the sea at great depths, by using thermometro- 
graphs of very excellent construction. Experiments of this kind have always 
excited much curiosity, because they give occasion to search how there occurs, 
under the tropics, those inferior beds in which the temperature appears to be much 
beneath that which the surface of the sea can acquire by radiation, and they ex- 
cite the zeal of seamen sc much the more at the present moment, as it appears 
to have resulted from some recent experiments, that salt water has not, like fresh 
water, a maximum of density previous to the degree of congelation ; and never- 
theless this has been made the starting-point in all discussions to which the dimi- 
nution in the temperature of the waters of the ocean have given birth. 
The great undertaking of which we have just presented the analysis, was exe- 
cuted by Mr. de Blosseville and Messrs. Legay and Vidal, whom the former had 
instructed in making observations, and whose zeal never for one moment abat- 
ed. We may add, that Mr. de Blosseville had procured, at his own expense, a 
part of the instruments which he employed. 
Among the detached labours which we have met with in the registers of the ex- 
pedition, we may mention observations on tides, the determination of the eleva- 
tion and temperature of some hot springs in Ceylon, and lastly, physiological ex- 
periments, in which Mr. Reynaud, chief surgeon of the ship, and Mr. de Blosse- 
ville, both assisted, upon the temperature of man, and of different animals. 
By choosing in the crew of the Chevrette, a good number of sailors of different 
countries, ages, and constitutions, these young observers have been able to mea- 
sure the modifications which different climates effect on the heat of the blood, 
and to add some interesting results to those which Mr. John Davy has already 
published on the subject. 
We have thus confined ourselves to the act of presenting to the Academy, the 
inventory of the different observations by which the voyage of the Chevrette has 
enriched science. It is not that we have always resisted the desire of draw- 
ing some consequences from them ourselves; but the difficulty of these de- 
ductions is so little when compared with that with which such numerous observa- 
tions must have been accompanied, under the burning sun of a tropical climate, 
that we have looked upon it as a duty, even with the risk of offering you a report 
rather devoid of interest, to leave entirely to the authors of the labour, the pleae 
sure of first publishing the results to which they may lead.” 
The commissioners, after stating that under every point of view, the journey of 
the Chevrette will occupy a distinguished rank among those voyages from which 
science has reaped the greatest benefits, proposed that the gratitude of the Aca- 
demy should be testified towards the zealous and intelligent officers, and hoped 
that, in the publication of the observations, the superintendence of each depart. 
ment would be given to those who had particularly occupied themselves with first 
collecting its materials. 
Account of Mr. Rifaud’s Travels. 
THE travels of Mr. Rifaud, which have occupied twenty-two years of that gen-. 
tleman’s life, out of which thirteen have been passed in Egypt, have excited much 
interest in France. 
The quantity of materials which he has collected is enormous. His drawings 
amount to more than six thousand. His notes are contained in fourteen manu- 
script volumes ; and his collections contain specimens of all kinds in the natural 



