S\i " Scientific Intelligence. [ArRlt,, 



here Di'. Wollaston's method of obtaining it, which I have likewise 

 tried, and find more productive than my own. 



Dissolve the soluble part of ktip in water. Concentrate the 

 liquid by evaporation, and separate all the crystals that can be ob- 

 tained. Pour the remaining liquid into a clean ves?el, and mix 

 with it an excess of sulphuric acid. Boil x\\h liquid for some time. 

 Sulphur is precipitated, and muriatic acid driven off. Decant off 

 tlie clear liquid, and strain it througli wool. Put it into a small 

 flask, and mix it with as much black oxide of manganese as you 

 used before of sulphuric acid. Apply to the top of the flask a glass 

 tube shut at one end. Then heat the mixture in the flask. The 

 iodine sublimes into the glass tube. Dr. VVoUaston informs me 

 that soapers' black ashes yield iodine in considerable quantity. Mr. 

 Tennant tried sea water without finding any in it ; so that it would 

 appear to be derived from the sea weed entirely. 



IX. Basaltic Rock near Nottingham. 



I have been fiivoured by the Rev. Mr. Toplis with specimens of a 

 basaltic rock which he found near some sand rock in a valley by the 

 side of the foot-path leading from Clifton to Barton, near Notting- 

 ham. The specimens which I received constitute a black porous 

 rock, vvith white particles in it. The appearance is strikingly 

 similar to that of Mr. Gregory VValts's fused greenstone ; and 1 

 cannot avoid tliinking it has undergone the action of heat. 1 cannot 

 gather from Mr. Toplis's information whether it was a rock in situ, 

 or a loose rock, from which he detached the fragments. The white 

 specks may be felspar ; but the mineral characters of the fragments 

 which I received are rendered so indistinct, eitlier l*y heat or the 

 %veather, that it would not be easy to determine the species to 

 •which they belong. In one of the stones there is a round nodule 

 of quartz. x\s Mr. Toplis's letter contains some valuable facts 

 respecting the mineralogy of the vicinity of Nottingham, 1 shall 

 insert the greatest part of it here : — 



" As I never heard of any basaltic rocks having been found m 

 this neighbourhood, I thought it deserving of notice : it is vesicular, 

 and has white quartz pebbles interspersed throughout it. 



" The only rock hitherto observed in the vicinity of Nottingham 

 is a white sandstone, containing also beautiful white quartz pebbles: 

 it seems in some respects to be sitnilar to the second sandstone for- 

 mation described by Professor Jameson. 



" Where this sandstone rock is covered with clay, considerable 

 quantities of gypsum, principally fibrous, occur ; as is the case on 

 Snenton Hill, within half a mile of Nottingham. There seems, 

 indeed, to be immense quantities of gypsuni in this part of the 

 county : it is in very large beds in the neighbourhood of Gotham 

 and tii.e adjacent villages/ and it a|)pears to extend itself from 

 Derbyshire quite through Nottinghamshire, great quantities being 

 found within a mile of Newark. I observed it aliout ;-500 yards 

 from the place where the cDclosed specimens were broken off." 



