Analyfis and ExperlminU with Sulphate of Strentian, (Jc. 39 



12. Prufliate of pot-a(h occafioned a flight blue tinge. 



The different varieties containing, fo nearly, an equal proportion of earth and acid, the 

 ftatement of a fingle analyfis will be fufficient for the whole. Should there be any difference 

 between thefe, it will probably be found in the Ham-green varieties, containing rather more 

 acid ; the quantity of fulphate of barites produced from it amounting to nearly 252 grains. 

 From the foregoing experiments, it appears that 200 grains of the fibrous variety contains : 



Strontian 116,5 



Acid of 2,24 . . . , . • 83,5 



With a fmall proportion of iron 



200,0 



In addition to the modes of diftinguifhing the two earths already noticed, we may ftate the 

 cryftallization of the fulphures. 



A warm folution of the fulphure of barites depofits, on cooling, an affemblage of feve- 

 ral very thin layers of inclined oval plates, terminating in points, and radiating from a centre, 

 while the fulphure of ftrontian runs into a bafe line fitpporting a iiumber of parallel perpen- 

 diculars, gradually lefi'ening fo as to form the diagonal of a fquare. 



The ftrontian earth in a ftate of purity frequently varies in its cryftallization, fometimes 

 depofiting folitary tables, and at others, arranging them in irregular lines. Both barites and 

 ftrontian combine with phofphorus, and exhibit familiar appearances to the phofphure of lime. 

 Mixed with a few grains of oxygenated muriate of pot-afh, and triturated in a mortar, an ex- 

 plofion took place. 



Note by the Editor. (Dr. Beddoes.J 



Mr. Clayfield has lately been informed that another variety of fulphate of ftrontites is foun 

 near Sodbury. Mr. Deriabin has feen a blueifti fibrous variety, from a coal-pit, near Dum- 

 barton. On a profeffional journey to the north, I was ftruclc at Kefwiclc with a fpecimen in 

 Mr. Hutton's colledtion, Xi^WeA Jiriated gypfum. It is an exceedingly beautiful white ful- 

 phate of ftrontian, from Alfton, as the label bears. From Mr. Hutton, I have alfo received a 

 blueifh fpecimen, cryftallized in rhomboidal tables, which I took for fulphate of ftrontian ; but 

 Mr. Clayfield finds it to be barites. It comes from Cleter-moor, Cumberland. I have 

 another from Newlands, Cumberland, having the exaft appearance of the fulphate of ftron- 

 tian from Ham-green, which requires further examination. Many fpecimens, fuppofed to be 

 baritic, will doubtlefs, on examination, prove to be ftrontitic. But the diftindion will re- 

 quire nice infpedtion, even from thofe moft verfed in the external characters of foflils. 



The following experiments were made, at my requeft, by a friend : — Twelve grains of car- 

 bonate of barites were given to a two-months old rabbit. In half an hour not much affedted 

 "—■ n hour nearly dead. — The barites had afted violently as a cathartic, and had produced 

 almoft general par^lyfis. In about two hours, the rabbit died much convulfed. The ftomach 

 was greatly inflamed ; the inner coat feparated from that below, lying in folds, and as if half 



macerated. 



