74 EIGHTH REPORT — 1838. 



water are, iodine, boracic acid, ammonia, silica, selenium. He also 

 found bromine. The Avaters of the Jordan are strongly contrasted with 

 those of the Dead Sea ; for they yielded to Mr. Murray only minute 

 traces of lime and magnesia and muriate of soda. 



Observations ami Experiments made upon an Instrument termed a 

 Magnet-Electrometer. By Lieut. Morrison, R.N. 



In this communication Lieut. Morrison repeats the assurance that in 

 the instrument of his invention the magnet deflects to the east when 

 the air is positively electrified, and to the west when negatively elec- 

 trified. 



He also states the results of some examinations of the action of the 

 instrument, made to determine the validity of an opinion which had 

 been advanced, that the deflections in this instrument depend on the 

 hygrometric state of the suspending string. The author declares that 

 the same phenomena happen when a fine silver wire is used instead of 

 the string. 



On tlie Production of Crystals of Silver. By Tiios. E. Blackwall. 



Having observed nearly two years since in his writing-desk, some 

 small crystals of silver which were firmly fixed upon a green substance 

 like malachite, the author inferred, from seeing also a piece of brass in 

 his desk, which fitted to the green mass, that there had been galvanic 

 action generated by the zinc and copper of the brass, and that by its 

 influence the nitrate of silver had been decomposed, and thus the silver 

 crystals formed. 



He describes experiments which he had instituted to test the truth 

 of this view, and mentions the production of very similar crystals by 

 the aid of corresponding metallic combinations. 



GEOLOGY. 



Observations on the Newcastle Coal-field. By John Buddle, F.G.S. 



This elaborate memoir, comprising a detailed account of the most 

 interesting phenomena of the coal formation round Newcastle, Avas di- 

 vided into several portions, entitled, 



Obsei'vations on the Newcastle coal-field. 



Strata of the Newcastle coal-field. 



Description of the sections of the seams of coal. 



Foreign substances in coal. 



Hitches and troubles. 



Dykes and faults. 



