a tiiiiierni Pruducl'ton fnun Dsvijiislurc. ;->.Q 



fpccimeu lost ciuht grains bv long continued ignition, after 

 which it easily dissoTvcd in the lixivium by heat, jcniving a 

 residuiuii of a'quarter (if a grain only, which was red oxide 

 of iron. The precipitate fro.m the solution of jiotash, niadc- 

 bv means of muriate of ;iininunia, w-cighed, when property 

 treated, 21 irrains. 



Several specimens were distiHc^l in the mruuier above de- 

 scribed, and in all ease* the water collected had sinnlar pro- 

 pel tics. The onlv test by which the presence of acid matter 

 in it could be detected was litmus paper; and in some cases 

 t,hc cflect upon this substance was barely perctptible. 



V. General Ol'scfvatlons. 



I have made several experiments with the hope of ascer- 

 tainin<T the nature of the acid n^atter in the water ; but, 

 from the impossibilit)' of procuring any considerable quan- 

 tity of the fossil, they have been wholly unsuccessful. It 

 is, however, evident, iron) the cx[crin)ents already detailed, 

 that it is not one of the known iiiineral acids. 

 . I am disposed to believe, from the minuteness of its pro- 

 portion, anil from the diilerencc of this proportion in dif- 

 ferent cases, that it is not essential to the composition of 

 the stone; and that, as well as the oxide of manganese, that 

 of iron, anil the lime, it is only an accidental ingredient; and 

 on this idea the pure matter of the fossil nmst be consKlered 

 as a cliemiial eonibinatiou of about thirty parts of water 

 and seventv of alumine. 



The experiments of ^M. Theodore dc Saussure on the pre- 

 cipitation* of alumine from its solutions, have demonstrated 

 the alKnity of this body fov water; but as yet I believe no 

 aluminous stone, except that which I have just described, 

 has been found, containing so large a proportion of water 

 as lliirtv paits in the hundred. 



The (iiaspore, which has Ix'tn cxaitiined bv I\I. A'auquc- 

 lin, and which loses sixteen or seventeen parts in the hun- 

 <lred bv iirni'iion, aiul which leonlains nearly cightv of alu- 

 mine, and only three of oxiiie of iron, is supposed bv that 

 excellent chemist to be a compound of alumine and water, 

 lis phvsical and chemical characters ditler, howe\er, very 

 jnuch from those of the new fossil, and other researches arc 

 wanting to ascertain whether the part of it volatilized by 

 heat is of the same kind. 



I have examined a fossil from near St. Austlc, in (\)vn- 

 Wiill, verv bimilar to the fossil fnnii Barnstaple \\\ all its 



* Journal de Plivsitnie, torn. Hi p. 'J HO. 



C 4 pcneval 



