CHEMISTRY. 209 



allowed to stand for 3 or 4 hours in a lukewarm dilute solution of 

 bichromate of potassium, to which a small quantity of nitric acid 

 has been added. After the expiration of this time the feathers 

 are found to have assumed a greenish hue, owing to the sesqui- 

 oxide of chromium deposited upon them ; in order to remove this, 

 use is made of a dilute aqueous solution of sulphurous acid, which 

 leaves the feathers perfectly white. The solutions should all be 

 dilute, and particular care exercised in the employment of the 

 nitric acid. — Dujiot in l>ingl. Pol. Journ. 



BLEACHING PALM OIL BY CHROMIC ACID. 



The following is a detailed account of the process used by M. 

 Engelhardt, of Leipzig, for bleaching palm oil by means of 

 chromic acid : A convenient quantity of palm oil is placed in a 

 caldron and heated to about 62° C, and allowed to repose dur- 

 ing a whole night; the next day it is poured into a perfectly clean 

 vessel, and cooled down to 40° or o7° C. While this operation is being 

 performed, a certain quantity of water is heated to ebullition ; for 

 1,000 parts by weight of palm oil, 45 of water; in this quantity 15 

 parts of bichromate of potassium are dissolved. As soon as the 

 solution has cooled a little, 60 parts of hydrochloric acid are added, 

 and it is then mixed with the palm oil, which is vigorously agi- 

 tated during the mixing. Five minutes suffice for the oil to be 

 colored a dull green. By continuing the stirring, the oxide of 

 chromium becomes completely separated, the oil becomes clearer 

 and clearer, and finally quite limpid ; when this point is arrived 

 at, it is washed with hot water ; the product is perfectly white. If 

 the palm oil has not been thoroughly bleached by the treatment, 

 the process is repeated with 23 parts of bichromate of potassium, 

 and one of hydrochloric acid. This method is capable of rapid 

 execution, and gives very good results. — Druggists' Circular. 



ALBUMEN. 



It frequently happens that among the dried albumen met with 

 in commerce a variety occurs which is soluble in water, but not 

 coagulated by heat. l)r. Monnier,of Lyons, has found that when 

 white of eggs is slowly evaporated by exposure to the heat of the 

 sun, or rapidly evaporated in a water-bath after exposure for a 

 considerable time to sunlight, a modification of albumen is ob- 

 tained, which is not coagulated b}^ heat. From a dilute aqueous 

 solution, this variet}' is not precipitated by acetic, formic, or tar- 

 taric acid, but on the addition of a few drops of either of these acids 

 it passes into the coagulable modiiioation. It was found that 5 

 milligrams of crystallized acetic acid in 0.5 c.c. of water were 

 suflicient to cause the conversion of 20 grams of this dry albumen 

 dissolved in 10 c.c. of water. When ammonia was added in suf- 

 ficient quantity to exactly neutralize the acid, the albumen passed 

 back into the modification not coagulated by heat. —Deutsche Ind, 

 Zeitung. 



18* 



