SOCIETY OF PHYSICS AND NATURAL HISTOEY, OF GENEVA. 349 



launch the balloons about 3 or 4 o'clock in the morning-, because at that 

 hour they were covered with dew, of which the gradual evaporation 

 lightened them during the morning hours, and allowed tbem to maintain 

 the same height witliout it being necessary to throw out balhist. Nu- 

 merous trials, which seem to have some success, have been made in 

 regard to directing baHoons, \mt have not yet been completed. 



The scarcity of food has induced many i)ersons attempt to imitate the 

 elements of first necessity, and M. Dumas has read on this subject a me- 

 moir in which he proves the im[)ossibility of producing milk artihcially. 

 The fabrication of this substance has been Impiently attempted and 

 has been practiced upon a great scale, but the artificial milk can never 

 take the place of the natural milk, for the latter exhibits an incontestable 

 organic structure which cannot be reproduced chemically ; the fat cor- 

 puscles are enveloped in a pellicle, which prevents ether from dis- 

 solving them. We hnd these globides with their i)ellicle even in the 

 milk extracted from the lacteal vessels at the moment when the secre- 

 tion of the glands takes place, which i)roves that they have a physio- 

 logical origin. M. P. Cap, who we all know has been remarkably assid- 

 uous at our meeting's, has read two papers concerning the history of 

 chemistry. The numerous historic notices which proceed from the pen 

 of this author are so well known to those who follow the progress of 

 science, that it is hardly necessary to mention how peculiarly well qual- 

 ified he is to treat these subjects. In his memoir upon the discovery of 

 oxygen he has proved that this body was in the first place discovered 

 by Bayat, a French chemist, fallen unjustly into oblivion, and that the 

 work of Priestley and of Scheele is confined to making known the 

 properties of oxygen, as well as those of its compounds. But Lavoi- 

 sier's eminently generalizing mind gave to this discovery its true import- 

 ance, and deduced from it its now recognized relations to the nomen- 

 clature and the science of chemical combinations. M. Cap has also 

 given an account of the discovery of iodine b}" Bernard Courtois, in 

 which he particularly dwells upon the first phases of this discovery, 

 and upon the biography of its author. These notices have appeared in 

 the Journal of Pharmacy, so it is not necessary for us to speak of them 

 further. 



NATURAL SCIENCES. 



Geology. — Professor Alphonse de Candolle has examined the ques- 

 tion whether in case the flora which exists should be reduced to a fossil 

 state, we would be able to discover any characteristic which would 

 determine in a precise manner the geological age of the strata in which 

 it occurs. Now, he has proved that there is no such general char- 

 acteristic among the i)lianerof]amous plants which are now found at 

 the surface of the earth, and it is not probable there exists any among 

 the cryptogamous plants. It has probably been the same at all other 

 epochs, and consequently the similarity between two geological strata, 



