OF THE SPINELLANE. 339 



that existing in the potash formed by the combustion 

 of potassium in muriatic acid gas, which consequently 

 may with much more propriety be regarded as the dry 

 alkali*. 



After these illustrations, I trust the former opinions, which Potash and soda 

 I ventured to bring forward, concerning the metals of the hides' 16 ° 

 fixed alkalis, will be considered as accurate, and that potas. 

 sium and sodium can with no more propriety be considered 

 as compounds, than any of the common metallic substances ; 

 and that potash and soda, as formed by the combustion of 

 the metals, are pure metallic oxides, in which no water is 

 known to exist. 



These conclusions must be considered as entirely indepen- 

 dent of hypothetical opinions, concerning the existence of 

 hidrogen in combustible bodies, as a common principle of 

 inflammability, and of intimately combined water, as an 

 essential constituent of acids, alkalis, and oxides. This part 

 of the inquiry I shall reserve for the conclusion of the lecture, 

 and I shall first consider the nature of the metal of ammonia, 

 and the metals of the earths. 



(To be continued.) 



II. 



Of the Spinellane : and some other fossil Substances, by 

 Mr. NosEf. 



iVlR. NOSE has described this substance in his mineralogy Spinellane 

 of the mountains of the Rhine. He found it on the banks where found. 

 of the lake of Laach, near Andernach. It is in a rock 

 composed of various substances, as oxide of iron, quartz, 

 hornblende, mica, and some other substances, to which he , 

 has given peculiar names, such as, 



* Consequently Mr. Berthollet's fused potash must contain nearly Water in 

 23 per cent of water. From my own observations I am inclined to potash, 

 believe, that potash kept for some time in a red heat contains 16 or 

 17 per cent of water, taking the potash formed by the combustion of 

 potassium as the dry standard. 



f Journal de Physique, vol. Ixix, p. 160. 



