210 GEOLOGICAL OBSERVATIONS IN FRANCE. 



Experiments ^t tlie school of mines of Montblanc a ffreat many expe- 

 at the School . ^ , , . , , , , . „ 



jj nments nave been made on the desulphuration of galena by- 



iron, the results of which were of sufficient importance, to 

 render the publication of them desirable. 

 Hints may he The Drcsent paper contains several facts applicable to the 

 facish^'^^"*^^^^*^*^^ metallurj^y, and capable of sugj^esting different ex- 

 given, periments to those who cultivate it. I have not pointed out 

 any, because they wilT readily suggest themselves to those, 

 who are capable of conducting them. 

 Mr. Descotils AH the experimental researches here given were made in 

 th3 «cpS-^ ^^® laboratory of the Council of Mines, and under the eye 

 meats. of Mr. Descotils, whose advice was of great advantage to 

 me, in giving them that accuracy, which he is accustomed 

 to observe even in the least operations. 



VII. 



Heights of various Places determined hy the Barometer, in 

 the Course of several Tours through France, Switzerland, 

 and Italy: 6^ F. Berger, M. D.y of Geneva*. 



Ascertauiing JtSlMONG the means best calculated to advance the phj*- 

 heights o^^^ ^^ gj^^l department of geography in the present state of our 

 the improve- knowledge we may reckon the ascertainment of the eleva- 

 ment of geolo- ^j^^j^ of a great number of points on the Earth's surface. 

 La Place The learned author of la Mecanique celeste has proposed to 



employ with this view observations with the barometer con- 

 jointly with the longitude and latitude, to obtain a more 

 complete and extensive levelling than trigonometrical mea- 

 surement will admit, and at the same time to acquire a 

 knowledge of the direction of mountainous chains, the slope 

 * of rivulets, and the forms of countries. To promote these 

 useful objects I shall add to the researches of these natural 

 philosophers, who have attended to this branch of physics* 

 the observations I have collected in different journies. They 

 will form the subject of a f'ewpapers, which I shall publish 



i * Abridged from the Journal de Physique, vol. LXlV, p. 220, March, 

 1807. 



