jg20.] Scientific Intelligence. 309 



liave always the very same bulk of peroxide of copper, and of 

 nmriate of lime, in the tubes. When these precautions are not 

 attended to, the quantity of common air evolved vanes so much 

 as to baffle all attempts to determine the quantity of azote given 

 out unless it be very considerable. These mceties would be of 

 Tery httle consequence if we could decompose quantities ot the 

 substances subjected to experiment amounting to 10 grs. ; but 

 this I have not hitherto been able to accomplish. 1 mix the 

 o-rain of naphtha with a little peroxide of copper, and let it down 

 fnto the boUom of the tube. By surrounding it with moist clay, 

 I keep it cool till the further extremity of the tube is red-hot. 

 I then remove the clay, and allow the bottom of the tube o 

 become hot enough to volatilize the naphtha completely, bhould 

 any ammoma or nitric acid be formed, they would be decom- 

 posed while passing through at least 12 inches cf red-hot 

 peroxide of copper. 



IV, Mount Canigou. 



Canigou is a celebrated mountain in the chain of the Pyre- 

 nees, sftuated in the part of France formerly called RousiUon, 

 and at present the department of the li/rcnees O'lcntales 

 According to the measurement of M. ^\f'f^\\'^J^^} 

 French toises, or 9150 Enghsh feet, above the level of the sea. 

 It was long considered as the highest mountain in the Pyrenees ; 

 thono-h it is now known that several exist in that extensive chain 

 which surpass it in heat by at least 2000 feet. 1 his mountain 

 lies west, and a little south from Marseilles, at the distance of 

 57 French leagues ; yet at certain seasons ot the year it is 

 perfectly visible from that city. Baron von Zach, while livinj 

 in Marseilles in 1808, resolved to verify this assertion ^vhlch had 

 been repeated to him by so many eye witnesses of the fact, that 

 he had no reason to disbelieve it. He considered it as likely that 

 the mountain would be visible only at those seasons of the year 

 when the sun set directly behind it. This he found co happen 

 about the beginning of February and the end of Marco. Ac- 

 cordinoly on Feb. 8, 1808, he went towards sunset to the top ot 

 the mountain Notre Dame de la Garde, accompanied by M. 

 Thulis, M. D'Aubuisson, M. Reboul, and M. Martin; and 

 provided with the requisite instruments to observe the mountam. 

 As soon as the sun was set, the mountam, and various other 

 peaks, appeared so distinctly that the spectators could hardly 

 persuade themselves that it was the Pyrenees which they saw ; 

 but rather some mountains in the neighbourhood of Marseilles. 



Baron von Zach found that the azimuth (or the angle witti 

 the line joining the Canigou and Marseilles makes with the 

 meridian) of the highest peak of the Canigou from the p ace 

 where he was placed was 71° 20' 8" south of west ; while that 

 of Mont Ventoux, near Avignon, was 4*^ 17' 27 north of west. 

 — (Correspondence Astronomique, i. 413.) 



.A. 



