On the Compofition of Azote, 371 



through the port of Safli are of a brown or red colour j but he attributes that colour to the 

 quantity of red oxide which is mixed with the foil of the province of Abda, in which this 

 part is fituated. This oxide communicates its colour even to the whiteft wool, and the in- 

 habitants of this province are known by the red tinge of their cloaths, which no procefs can 

 totally deftroy. 



In the months of Meffidor and Thermidor, when heavy dews fall, the gum lofes 

 much of its clearnefs and other qualities for which it is defirable. 



An hundred pounds weight of this fubftance coft, in the year 1793, at Mogador, about 

 48 francs of our money, exclufive of 5 francs 70 cents for cuftom-houfe duties. 



The inhabitants of Morocco do not appear to apply this gum to any purpofe whatever i 

 they fell all that they can gather to the commercial nations of Europe. 



VIII. 



Remarks on the Memoir in which M. Girtanner examines whether Azote be a Jimple or a ' 

 compound Body. By Cit. Bertholllt*. 



OOME experiments were long fince made by Dr. Prieftley, which, at firft, induced him 

 to believe, that water diftillcd with lime, and particularly with clay, or indeed without 

 any addition, in an earthen retort, or a retort of glafs, deprived of its polilh, became 

 changed into air. But he found that this dedu£lion was erroneous, and that it was 

 merely a tranfmiflion of the furrounding air which gave rife to the circumftance. Guyton 

 added fome obfervations to thofe made by Prieftley (Encyclop. Vol. I. p. 674), and the 

 fatl appeared to be clearly accounted for. 



Neverthelefs, Wiegleb publiflied a memoir, in which he pretended to prove, by his 

 own, and by fome other experiments, that the gas which is obtained by paffing water 

 through red hot earthen tubes might be attributed folely to the combination of the aqueous 

 vapour with the matter of heat, and that this combination formed azote gas. 



This memoir occafioned a reply which was publiflied by Dieman, Van Tfootwyk, and 

 Lauwerenburg. Thefe learned chcmifts carefully examined every circumftance which had 

 apparently eftabliftied the pretended production of azote gas from water; and.I fliould 

 have thought that there could exift no doubt refpe£ting the confequence which they drew 

 from their experiments, which was, " that the azote gas which, in fome cafes, is ob- 

 *' tained by pafting water in vapour through ignited tubes, proceeds merely from the 

 ".external air, deprived of its oxygen gas by the fire in which the tubes are placed; and 

 *' that, thus, the pretended converfion of water into azote gas, by its combii^ation with 

 *' the matter of heat, is overthrown." 



* Annales de Chimie, XXXV. 23. The memoir refcned to is ioferted in our Journal, and is con- 

 cluded at p. 175 of the prefent volume. 



3 B 2 After 



