SALTS OF BARYTES. 487 



parts of boiling water, and in 20 parts of water at 6*0. Mr. 

 Smith finds this hydrate to contain 9HO, of which it loses 7? by 

 a moderate heat, and 1 additional, by a stronger heat. Barytes 

 retains 1 eq. of water with great force like the fixed alkalies. 

 This combination is fusible a little below redness, and runs like 

 an oil ; it congeals into a crystalline mass, which attracts car- 

 bonic acid very slowly from air, and is therefore the most fa- 

 vourable condition in which to preserve hydrate of barytes. 



The solution of barytes is strongly caustic, although less so 

 than potash or soda; and, in common with all the soluble pre- 

 parations of barium, it is poisonous. It is used to remove car- 

 bonic acid from air and other gases (page 280). Barytes, 

 whether free or in combination with an acid, as a soluble salt, 

 is discovered by means of sulphuric acid, which throws down 

 sulphate of barytes, a compound not decomposed by, nor solu- 

 ble in, nitric and hydrochloric acids. 



Peroxide of barium; Ba O 2 ; 1056'. 9 or 84.69. This com- 

 pound is prepared by exposing anhydrous barytes to pure 

 oxygen at a red heat ; or by heating pure barytes to low red- 

 ness in a porcelain crucible, and then gradually adding chlorate 

 of potash, in the ratio of about 1 part of the latter to 4 of the 

 former. The chloride of potassium is removed, by cold water, 

 from the peroxide of barium formed at the same time, while 

 the latter forms a hydrate with 6HO (Liebig and Wohler.) 

 Peroxide of barium, when decomposed by dilute acids with 

 proper precautions, affords peroxide of hydrogen. 



Chloride of barium; BaCl + 2HO; 1299.6 + 225, or 

 104.83 + 18. A re-agent of constant use, which is obtained by 

 dissolving native carbonate of barytes in pure hydrochloric acid 

 diluted with 3 or 4 times its bulk of water, or by neutralising 

 sulphuret of barium by the same acid. It crystallizes from 

 a concentrated solution in flat four-sided tables, bevelled at the 

 edges, very like crystals of heavy spar. The crystals contain 2 eq. 

 of water, (14.75 per cent), which they lose below 212. They are 

 said to be soluble in 400 parts of anhydrous alcohol : 100 parts 

 of water dissolve 43.5 at 60, and 78 at 222, which is the boiling 

 point of the solution. 



Carbonate of barytes ; Ba O, CO 2 ; 1233.3, or 98.83. This 

 salt consists in 100 parts of 22.41 carbonic acid, and 77-59 ba- 

 rytes. The density of the native carbonate is 4.331. It re- 

 tains its carbonic acid at the highest temperatures. The 



