Cavities containing Fluids in Rock-Salt. 113 



evident that the fluid contains no sulphuric acid. Oxalate of 

 ammonia gives a slight precipitate, which shews the presence of 

 a small portion of lime ; and as carbonate of potash throws down 

 a dense precipitate, magnesia is clearly the principal ingredient 

 with which the muriatic acid is combined. The fluid in the ca- 

 vities of rock-salt may therefore be considered as a saturated so- 

 lution of muriate of magnesia, mixed with a little muriate of 

 lime ; and as the salt itself, when free from cavities, gives no 

 indication of either of these, or of any other foreign matter, it 

 may be considered as pure chloride of sodium. 



List q/' Geological and Mineralogical Collections in Great Bri- 

 tain and Ireland- 



I. ENGLAND. 



Buckinghamshire. — Duke of Buckingham's, (contains the mineral 

 cabinet of Ilaiiy). Stow. 



Cambridgeshire. — At Cambridge, the Woodwardian Collection, be- 

 longing to the University, augmented by Professor Sedgwick, &c. 



Cornwall. — Royal Geological Society of Cornwall, Penzance, (a ge- 

 neral collection of Cornish rocks and minerals). Williams, Esq. 

 Scorrier House ; and Rashly, Esq. of Menabilly, (su^evh collec- 

 tions of Corjiisili minerals) ; iMudge, mineral-dealer, Falmouth. 



Cumberland. — Huttou's and Crossthwaite's collection, Keswick, (mi- 

 nerals and rocks of tlie county). 



Derbyshire. — W^hite Watson at Sakewell, mineral-dealer ; Brown 

 and .Maive at Derbi/, and at Castleton (collections for sale). 



Devonshire. — Johnson, Esq. Exeter (Devonshire minerals). Philoso- 

 phical Institution, Exeter. Reverend Mr M. Every, Torquay, (in- 

 teresting collection of fossil bones from that neighbourhood). 



Dorsetshire. — Miss Phillpotts, Lyme Regis, (lias fossils); Miss 

 Anning, Ditto, (specimens for sale) Colonel Gordon, Shaftesbury, 

 (fossils). 



Durham Marquis of Cleveland, Raby Castle, (splendid collection 



of fluors and calc spars from the lead-mines of Alston and neigh- 

 bourhood). 



Essex. — Philosophical lii>iitution, Colchester. Mr Dyk's collection of 



frag fossils, Harvnch. 

 GLOUCESTEnsHiRE — At Bristol, the Philosophicallnstitution inParlia- 

 ment Street contains a good collection of specimens, illustrating the 



APUIL JUNK 1829. H 



