CHEMISTRY. 



air, it speedily deliquesces. A strong heat decom- 

 poses it. When dried in high temperature, it is very 

 caustic. 



Sp. 3. Muriate of Ammonia- and-Magnetia. This 

 salt is obtained when the solutions of the two last 

 salts are mixed together. Its crystals are small and 

 irregular, its taste bitter and ammoniacal. It dis- 

 solves in about six times its weight of cold water. 



Sp. 4. Muriate nf Alumina. This salt is always 

 in the state of a supermuriatt. It hardly crystallizes, 

 being always either gelatinous or in the state of a 

 white mass. Water dissolves about four times its 

 weight of it. It speedily deliquesces in the air. Al- 

 cohol dissolves at least half ita wight of this salt. 

 When heated, it melts and loses its acid. 



Sp. 5. Muriate of Ytiria. This salt docs not 

 crystallize, but runs to a jeliy. It melts in a gentle 

 heat, and attracts moisture very rapidly from the at- 

 mosphere. 



Sp. 6. Pinnate of Glucina. This salt has a sweet 

 taste, and readily crystallizes. 



Sp. 7. Muriate of Zirconia. This salt is transpa- 

 rent, and crystallizes in needles, which effloresce in 

 the air. It is very soluble in water and in alcohol. 

 Heat decomposes it with facility. 



The following Table exhibits the composition of 

 these salts according to the most accurate experi- 

 ments hitherto made : 



" f 

 Chrmi:rv. 



The last species has not hitherto been analy- 

 sed. 



GENCS II. Fluates. 



Kluatcs. Most of these salts are but sparingly soluble in 



water, and hitherto they have been but superficially 

 examined. When sulphuric acid is poured on them, 

 they exhale acrid fumes, which readily act upon glass 

 and corrode it. 



Sp. 1. Fluate of Potash. This salt is hardly 

 known. It is said to crystallize when pure. It has 

 but little taste, dissolves readily in water, and melts 

 when heated. It combines readily with silica, and 

 forms a white powder, loose like chalk, containing 

 an excess of acid. 



Sp. 2. Fluate of Soda. This salt crystallizes in 

 cubes. Its taste is bitter and astringent. It is spa- 

 ringly soluble in water. When heated, it decrepitates 

 and melts into a transparent globule. 



Sp. 3. Fluate of Ammonia. This salt crystallizes, 

 and may be sublimed without decomposition. 



Sp. 4. Fluate of Alumina. This salt does not cry- 

 stallize, but is easily obtained in the state of a jelly. 



Its ta<te is astringent, and it always contains an ex- 

 cess of acid. 



The remaining fluates are insoluble in water. 



Sp. 5. Fluate of Magnesia. When this salt con- 

 tains an excess of acid, it may be obtained in dode- 

 cahedrons. Heat does not decompose this salt. 



Sp. 6. Fluate of Lime. This salt occurs native 

 in abundance, and is the only fluate that has been ac- 

 curately examined. It is usually crystallized in cubes, 

 sometimes in octahedrons. It has no taste, nor is it 

 altered by exposure to the air. Its specific gravity 

 is 3.15. When heated, it decrepitates and phospho- 

 resces strongly. When strongly heated, it melts into 

 transparent glass. According to Dr Thomson's ana- 

 lysis, it is composed of 32f acid and 67 \ lime. 



Sp. 7. Fluate of Barytrs. This is a white taste- 

 less powder, not hitherto examined. 



Sp. 8. Fluate of Alumina and- Soda. This salt has 

 been found in Greenland, and is called cryolite by 

 mineralogists. Its colour is greyish white. It has 

 some transparency. It breaks into cubic fragments. 

 Its specific gravity is 2.950. It is brittle and softer 

 than fluate of lime. It is composed of 

 Acid and water, 40 

 Soda, 36 



Alumina 24 



100 



Sp. 9. Finale of Silica. Fluoric acid, as usually 

 obtained, contains, in solution, a quantity of silica. 

 When kept in vessels not completely shut, it depo- 

 sites small rhomboidal crystals of silica. 



GENUS III. Borates. 



This genus has been very imperfectly examined. Boratts- 

 All the fluates, before the blow-pipe, melt into a 

 glass. When boiled in diluted sulphuric acid, they 

 yield small scales of boracic acid. 



Sp. 1. Borate of Potash. This salt crystallizes 

 in four-sided prisms. It has been very little examined. 



Sp. 2. Borate of Soda. This salt may be formed 

 by saturating borax with boracic acid. It is soluble 

 in 2^ times its weight of hot water. 



Sp. 3. Borax or Sub-borate of Soda. This salt 

 is the only one of the borates which has been accu- 

 rately examined. It is brought from the East Indies, 

 and has been in common use in Europe for ages. It 

 seems even to have been known to the ancients. It cry- 

 stallizes in hexangular prisms, but is usually in round- 

 ish Semi-transparent lumps. Colour white. Specific 

 gravity 1.740. Taste styptic and alkaline. Converts 

 vegetable blues to green. Soluble in about twenty 

 times its weight of cold water, but more soluble in 

 hot water. When exposed to the air, it effloresces 

 slowly and slightly. When heated, it melts, loses its 

 water of crystallization, and is converted into a light 

 porous substance called calcined borax. In a strong 

 heat it melts into a transparent glass, still soluble in 

 water. It is said to be composed of 

 Acid, 39 

 Base, 17 

 Water, +4 



100 



