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XIV. Report made to the Class of the Physical and Ma- 

 thematical Sciences of the French National Institute^ by 

 C. Ramon, respecting a Memoir of C. Daubuisson on 

 the Basaltes of Saxony *. 



L. Hauy and myself have been charged to give an ac- 

 count to the class of a very long and circumstantial memoir 

 of Daubuiason on the basaltes of Saxony, accompanied with 

 observations on the origin of basaltes in general. It is 

 well known that the question respecting the origin of ba- 

 saltes has excited many disputes and discussions among na- 

 turalists. It is, however, among the small number of sub- 

 stances which it is impossible to mistake in the antient 

 mineralogy. Pliny and Ptolemy give this name to the lapis 

 JEtkiopicus of Herodotus and Strabo ; a stone which was 

 found in Upper Egypt, on the frontiers of Ethiopia, and 

 which, according to the latter author, appeared always under 

 a regular form. According to their description, it was of 

 the colour and hardness of iron ; it was employed in dif- 

 ferent works of sculpture, and particularly for making mor- 

 tars. No object of natural history has been described with 

 more precision bv the antients ; and a great number of 

 works of this basaltes, still preserved, afford us the means of 

 fully examining the nature of it. 



•Dolomieu, to whom we are indebted for these details, ' 

 examined the antique basaltes with great care. He found 

 in it what is called schorl en masse, hornblend, trapp, pe- 

 trosilex, granitella composed of feld-spar with grains more 

 or less perceptible, and scales of schorl : he found the com- 

 ponent parts vary in their volume and proportions, and in 

 the same masses veins and spots of granite on the smooth 

 black ground of the stone : he therefore declares, with every 

 assurance of conviction, that basaltes is not of volcanic 

 origin. 



Twenty years before, our fellow-labourer, Desmarets, 

 made similar observations ; and he deduced exactly the 

 rame consequences, describing under the name of %abbo 

 I he amphibolic stones which Dolomieu calls hornblende 

 mid schorl en masse. 



The idea of the volcanic origin of the antient basaltes, 

 continues Dolomieu, arose from the physical constitution 

 of Italy, where people must have been gradually accus- 

 tomed to consider all stones not calcareous, and of a black- 



* From the Annates de Chimie, No. 137. 



ish 



