1835.] Improvements in Science. 193 



solution of alkaline crenate is mixed with a solution of 

 'chloride of calcium. The solution of this salt leaves behind 

 it a yellow transparent varnish. It dissolves completely in 

 water. When the neutral salt is mixed with excess of acid, 

 evaporated, and then treated with alcohol, a pale yellow 

 acid salt remains, easily soluble in water. A basic salt is 

 obtained by mixing lime-water with the neutral salt. 



Crenate of Magnesia is very soluble in water. 



Crenate of Alumina is insoluble in water, but the acid 

 salt is soluble. Ammonia does not precipitate the base, 

 but affords a double salt by evaporation, which is soluble, 

 and affords pure alumina by calcination. The neutral 

 crenate has a portion of its alumina precipitated by 

 ammonia. 



Crenate of Manganese is a pale yellow powder. 



Crenate of Iron is soluble in water. It may be obtained 

 from the ochre, by mixing the latter with water, and passing 

 a current of sulphuretted hydrogen through it. By evapo- 

 ration in a place free from air this salt remains. 



Percrenate of Iron may be formed by adding crenic acid 

 to a solution of sulphate or chloride of iron. It is dirty- 

 white when dry, and earthy reddish-gray when moist. It 

 dissolves completely in ammonia. 



Crenate of Lead is produced when crenic acid is poured 

 into a strong solution of acetate of lead as long as the 

 resulting precipitate exhibits a brown or dark-yellow 

 appearance. When this ceases, the crenic acid is to be 

 dropped into the acetate of lead, the precipitate washed 

 with water, or rather with alcohol, and dried in a receiver, 

 over sulphuric acid. When dry it is a light-gray powder, 

 and is to a certain extent soluble in water. It is also soluble 

 in acetic acid, and somewhat in crenic acid. 



Crenate of Copper is precipitated from the acetate, but 

 not from the sulphate, by crenic acid. The precipitate is 

 it first dirty-white, and then light-gray, with a yellowish 



'een tinge. It is little soluble in water. Its precipitation 

 is not complete in the cold, but is fully effected at a 

 temperature of 50° (122° F.) 



An acid salt is formed by the addition of crenic acid to 

 the neutral salt. It is a gum like mass, insoluble in alcohol. 



Crenate of Mercury forms a yellow flocky precipitate, and 



VOL. I. O 



