Intelligence and Miscellaneous Articles. 463 



—A series, consisting of more than 300 Rock specimens, illustrative 

 of the Geology of the Northern and Central part of Cornwall. By- 

 Henry S. Boase, M.D. — Three additional specimens from the neigh- 

 bourhood of Liskeard. By the Rev. Canon Rogers. — A series of spe- 

 cimens in illustration of the Geology of Dartmoor, with a memoir. 

 By John Prideaux, Esq. of Plymouth. — A series of Rocks and Or- 

 ganic Remains from Yorkshire. By the Yorkshire Philosophical So- 

 ciety. — Specimens from the Manganese Beds near Tavistock, and 

 some specimens of Greenstone Slate ; also, specimens of Schorl Rock 

 from Park Wood. By Mr. W. J. Henwood. — A series of specimens 

 from the Garth Mine. By Joseph Carne, Esq.— Quarterly Mining 

 Review, Nos. 1, 2, 3. By Henry English, Esq. the editor. — Geolo- 

 gical Notes. By the author, Henry Thomas De la Beche, Esq. F.R.S. 

 &c. — Asiatic Researches. By the Asiatic Society. 



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New Members : Edward Collins, Esq. Truthan ; the Rev. Michael 

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LXXI. Intelligence and Miscellaneous Articles. 



ON THE SESgUIPERSULPHATE OF MERCURY. BY LIEUT. 

 W. T. HOPKINS, UNITED STATES. 



" Having had occasion, lately, to pour strong nitric acid on the 

 yellow neutral persulphate of mercury, known as the ' turpeth mine- 

 ral,' 1 observed that a portion of the salt disappeared, while the re- 

 mainder was converted into a white powder. This substance was 

 readily reconverted by water into the yellow salt. I succeeded how- 

 ever in edulcorating a portion of it without change ; and upon boil- 

 ing thirty grains of it with nitrate of baryta, digesting afterward with 

 nitric acid, (to remove a portion of peroxide of mercury which was 

 deposited,) washing, drying, and weighing, I obtained ] 9 grains of 

 sulphate of baryta. Now 19 grains of sulphate of baryta contain 

 6*44 grs. of sulphuric acid, and the white powder submitted to experi- 

 ment consisted of sulphuric acid, 6"44 grs. + peroxide of mercury, 

 23'56 grs. = 30. We have therefore the proportion 



23-56 : 6-44 :•. 216 : 59-04 



where 216 represents the atom of peroxide of mercury, and 59"04 the 

 quantity of sulphuric acid that would combine with it to produce the 

 compound under examination. If the numbers I had obtained had 

 been 6*48 and 23'52, the proportion would have been 



23-52 : 6-48 : : 216 : 60 



and 



