recently carried on in the Russian Empire. 293 



serving and interrogating nature by experiment,) the instru- 

 ments which belonged to the great age of Gahleo, of Huy- 

 ghens, and of Fermat, we should have now known, by compa- 

 rative observations, if the height of the atmosphere, the quan- 

 tity of water which it contains and precipitates, and the mean 

 temperature of places have diminished since those times. We 

 should have known the secular changes of the electro-magnetic 

 charge of our planet, and the modifications which may have 

 taken place, either from an increase of radiation, or from inter- 

 nal volcanic changes, in the temperature of the different strata 

 of the globe, which increases with the depth. We might have 

 known, in short, the variations in the level of the ocean, the 

 partial perturbations which the barometrical pressure produces 

 in the equilibrium of its waters, and the relative frequency of 

 certain winds, depending on the form and condition of tlie sur- 

 face of continents. M. Ostrogradsky would have submitted 

 to profound calculations these data, accumulated for centu- 

 ries, as he has recently resolved with success one of the most 

 difficult problems in the propagation of waves. 



Unfortunately, in the physical sciences the civiHzation of 

 Europe is not of remote date. We are, as the priests of Sais 

 said of the Hellenes, a new people. The almost simultaneous 

 invention of those organs which bring us nearer to the material 

 world, as the telescope, — the thermometer, — the barometer, — 

 the pendulum, and that other instrument, the most general and 

 powerful of all, — the infinitesimal calculus, are scarcely older 

 than thirty lustra. In this conflict of the forces of nature, a 

 conflict which does not destroy stability, the periodical varia- 

 tions do not seem to go beyond certain limits : They cause the 

 whole system to oscillate (at least in the present state of things, 

 since the great convulsions which have buried so many genera- 

 tions of plants and animals,) round a mean state of equilibrium. 

 But the value of the periodic change is determined with a de- 

 gree of precision proportional to the interval which has elapsed 

 between the extreme observations. 



It is to scientific bodies which are renewed without interrup- 

 tion ; it is to academies, — to universities, — to different learned 

 societies in Europe, in the two Americas, at the southern ex- 

 tremity of Africa, in India, and in that Australasia lately so 



