J20 ON T H £ BORACITE. 



covered by a ftrong pellicle. The workmen break the pellicle, 

 and the falts inftantly moot. Cryftallization, under fuch cir- 

 cumftances, is often immediately excited by gently running a 

 faline liquor from one gutter into another gutter. 

 Elcftricity Is of Saline liquors, under an improper atmofphere, will not form 

 regular cryftals, but accrete into fhapelefs lumps. The elec- 

 tric and non electric ftates of the atmofphere govern cryftalli- 

 zation. Many a maker of Glauber falts becomes fatigued from 

 not underfianding the latter circumftance. 



Iffe& of froft in From what has been faid, the young chemift muft not fuppofe 

 thefeexpen- . , , , , 



ments. that the elective attractions are altered, and the new com- 



pounds in thefe experiments created by means of froft. From 

 fulphate of magnefia and muriate of foda, fulphate of foda and 

 muriate of magnefia can be obtained without froft. Froft only 

 poffefles a readier power of converting, from what was formed 

 in a large portion of fluid, Glauber fait or fulphate of foda, 

 fpeedily, from a hot liquid into a cold fluid ft ate. The appa- 

 rent caufe confifts in the power of fevere froft in fuddenly dif- 

 placing the caloric, which becomes a difaggregative power. 



H. CAMPBELL. 



21, Fleet Street, May 20, 1802. 



XIII. 



Note of Citizen Vauquelin refpecling the Boracite, called 

 Magnefio-calcarcous Borate by the French Chemijls. 



Component parts J[ HIS foffil, of which the properties have afforded a number 

 o e oraci e. ^ interesting obfervations to philofophers and mjneralogifts, 



has been analyzed for the firft time by M. Weftromb, who 



found it to contain, 



Boracic acid 68 



Magnefia ... 13,05 

 Lime - - - 11 



Alumine - - 1 - 



Oxide of iron - - 0,75 



Silex - - 2 



95,80 



Citizen 



