390 Miscellaneous Intelligence. 



strontia, and lime. These salts are permanent out of contact of 

 the air, and when decomposed by muriatic acid, yield pure gallic 

 acid and muriates ; 0.2 grammes of gallic acid, dissolved in 2 cubic 

 centimetres of potash water, and placed in contact with 2 1 cubic 

 centimetres of oxygen, became green and absorbed oxygen. After 

 a quarter of an hour the absorption was 7.5 cubic centimetres; 

 after three-quarters of an hour 12 cubic centimetres ; in 15 hours 

 14.5 cubic centimetres. Muriatic acid then disengaged 10 cubic 

 centimetres of carbonic acid, including that held in solution, and 

 the acid liquor precipitated gelatine. 



When the alkali is in excess, the colour developed is red, and 

 the absorption of oxygen more rapid and greater. By the suc- 

 cessive addition of portions of potash and oxygen to 0.2 gram- 

 mes of gallic acid, it ultimately absorbed as much as 58 cubic 

 centimetres of oxygen. 



The same phenomena took place with the neutral gal late of 

 baryta, or the gallate with excess of baryta. 



Ox gall with alkali out of the contact of air, undergoes no change 

 in colour ; with access of oxygen the gas is absorbed, and the 

 colour disappears. 



Colouring matter of blood and albumen. The colouring matter 

 with potash water absorbs oxygen, and becomes of a green yellow 

 colour ; out of contact of air, it was, after six weeks, still of a 

 reddish brown colour. Serum of blood and white of egg also 

 caused absorption of oxygen. 



Empyreumatic oil. An empyreumatic oil, from the distillation 

 of a fat body, at first of a light yellow colour, slowly became brown 

 by absorbing oxygen; but mixed with potash, it absorbed oxygen 

 rapidly, and quickly took a deep brown colour. 



Lignine Sugar and Starch. The experiments of M. Braconnot * 

 on the action of alkali on lignine, and the production artificially 

 of ulmin, are well known. M. Chevreul mixed wood with solution 

 of caustic potash in a retort, the beak of which plunged into 

 mercury, and then applied heat. The water was first evaporated, 

 then action took place, and an inflammable gas was liberated, 

 containing very little carbon ; the residue was of a light yellow 

 colour, and by the addition of water freed from air, no deeper 

 colour was communicated ; when oxygen was admitted, there was 

 rapid absorption, the colour became dark, and the ulmin or matter 

 described by M. Braconnot appeared. 



Many important considerations are derived from these facts, 

 such as the necessity of considering the probable action which 

 will be induced by the use of caustic alkalies in the separation of 

 proximate vegetable principles, such as gallic acid, vegeto-alkalis, 

 colouring matter, <^c. The following questions are also suggested, 



* Quarterly Journal, viii. p. S92. 



