which felt from the Clouds ?? ear V'dle-Franche. 223 



aggregation have undergone a certain degree of heat ; an 

 aspect whicli inav be better distinguished than described^ 

 In regard to the tilobular bodies, they cannot be the result 

 ©t"a kind of fusion, since they have none of the characters 

 of glass ; and being the most refractory of all those sub- 

 •tanccs of which the stone is composed, thcv could not pass 

 to the state of vitrification near pyrites, which, though the 

 least alterable substance, has nevertheless retained its Taniel- 

 lated texture. 



" The ])aste or earthy part even in small fragments ex- 

 periences in nitric acid a partial solution without losing its 

 cohesion, and being before susceptible of attraction by the 

 magnet is not so afterwards : which announces that the iron 

 only has been attacked by the acid. It however still retains 

 some metallic grains, which are pyrites. Treaited by the 

 blowpipe it gives black frit, assumes the metallic aspect, 

 and continues to be attractable. 



" I shall not give the specific gravity of this stone : as 

 it is not homogeneous, and as its gravity depends on the 

 greater or less quautitv of metallic particles, and especially 

 on the iron Ibund in it, no positive character can be de- 

 duced from this propcrtv. 



" To conclude : I can assert that the earthy part of the 

 interior of this mass, as well as each of the contained sub- 

 stances, is in its original state, and that the only changes 

 which the fire has eflectcd are the relaxation in the tissue 

 which I have already mentioned ; and perhaps the change 

 of colour, in case it has a particular one. I have also reason 

 to think that in certain respects, and particularly in regard 

 to texture, it approaches some kinds of pot-stone or sili- 

 ceous serpentine containing metals. 



" I shall conclude this description by transcribing; the 

 letter in which \'iiut]ue!ii) communicated to me the result 

 of the analysis he made of this stone ;— ' The stone which 

 you gave me to analyse (says he) consists of 



Silex - 1 - - - 46 



Oxidated iron - - - "R 



Maunesia - - - - 15 



Nickel ----- t; 



Lime ----- 3 



103 



♦"This stone is directly attacked by acids. By the ef- 

 fect of this action sulphurated hydrogen gas is constantly 

 devcluped. Tlie liquors resulting frou) the solutiou of this 



3 lone 



