284 VII. EARTHS AND ALKALIES.— 



receiver containing pearlash 6 oz. dissolved in water 31b. ; when 

 the distillation is finished, evaporate the liquid in the receiver 

 slowly in the dark ; the oxymuriate will crystallize first in flakes : 

 stimulant, gr. j — iij ; explodes when struck, or dropped into acids. 

 Used for making matches for instantaneous lights, and for pro- 

 curing oxygen gas. 



Bleaching liquid, Eau de Javelle, Aqua alkalina oxymu- 

 riatica. Common salt lb. ij, manganese lb. j ; water lb. ij, put 

 into a retort, and add gradually oil of vitriol lb. j ; pass the vapour 

 through a solution of subcarb. of potash Siij in water ,^xxix, 

 applying heat towards the last. Specific gravity is 1*087 ; sti- 

 mulant, antisyphilitic. Used to bleach linen, take out spots, and 

 to purify air impregnated with putrid exhalations. 



Salt of sorrel, Quadraxalate of potash, Sal acetosellce verus, 

 Potassoe oxalas. From the leaves of wood sorrel bruised and 

 expressed ; the juice is then left to settle, poured off clear, and 

 crystallized by slow evaporation ; 1 cwt. of wood sorrel yields 

 5 or 6 oz. 



2. From the leaves of sheep's sorrel, treated in the same 

 manner. 



3. By dropping subcarbonate of potash-water into a saturated 

 solution of oxalic acid in water, when it precipitates, and may be 

 separated by filtration : if two much alkali is added, it is taken 

 up, and will require an addition of the acid to throw it down 

 again ; cooling. Used to make lemonade and whey. 



ViTiMOLATED TARTAR, Tartarum vitriolatum. Dissolve green 

 vitriol in water, precipitate with oil of tartar, wash the precipi- 

 tate, filter, evaporate, and crystallize. 



NiTRUM viTRiOLATUM, Kail vitriolatum, PotasscB sulphas. 

 Dissolve the residuum left in distilling Glauber's spirit of nitre in 

 water; add subcarb. of potash, if necessary, to saturate any 

 superfluous acid, evaporate and crystallize. 



2. Evaporate the liquid that is left in making magnesia alba, 

 and crystallize : aperient and deobstruent, 3j to 5SS ; cathartic, 

 Siiij to 3vj : useful in visceral obstructions. Being very hard, it 

 is used in compound powders to divide jalap or scammony while 

 triturating with them. 



Sal ENixuM. Boil the residuum left in the distillation of 

 saltpetre with green vitriol, strain and evaporate to dryness. Used 

 as a flux by silversmiths and platers; also to adulterate cream of 

 tartar, and being powdered and rubbed into the wood with a hard 

 brush, to stop the ravages of the dry rot. 



PoTAssjs supERsuLPHAS. Dissolvc the salt that remains in 



