330 Mr. Everitt on Garden Bhubarb as a Source of Malic Acid. 



certainly proved to be phosphate, being made into an alka- 

 line phosphate and tested by silver and other means. To 

 the solution which filtered from the mixed sulphate and phos- 

 phate, containing excess of nitric acid, nitrate silver was added 

 and 4*1 of chloride obtained; to the solution filtered from 

 the chloride of silver, excess of hydrochloric and sulphuric 

 acids were added to remove the excess of silver and baryta : 

 the filtered liquid evaporated to dryness and ignited, after 

 putting on it excess of sulphuric acid, gave 39*3 grains of 

 a white salt, quite soluble in water (sulphates of soda and 

 potassa) ; these were dissolved in a minimum of water, and 

 excess of crystals of tartaric were added; the granular pre- 

 cipitate washed with dilute alcohol, weighed 33*3 ; the solu- 

 tion from the bitartrate of potassa evaporated and ignited, then 

 treated with sulphuric acid, evaporated again to dryness and 

 ignited, gave of dry sulphate of soda 4*7 ; this was dissolved 

 in water, and being slowly evaporated, the characteristic cry- 

 stals were formed. 



From the above data, and from some subsequent experi- 

 ments on a much larger quantity of juice, an imperial gallon 

 (sp. gravity T022), contains nearly, of 



Malic acid dry 11 139*2 grains. 



Oxalic acid dry 320*6 „ 



Potassa combined with organic-chlo-" 



ride, soda, sulphuric and phosphoric 



acids, traces of silicon and a little 



vegetable extract 



229*6 



If to obtain malic acid be the only object, slaked lime made 

 into a sort of cream with water might be added to the ex- 

 pressed juice, till the solution became slightly alkaline ; it 

 might then all be boiled and filtered, then proceed with the 

 nitrate of lead and the rest of the steps above described. To 

 procure the malate of lead in good crystals, some precautions 

 are necessary. From the precipitate suspended in water and 

 heated, a few grains only fall on cooling ; from 2 pints I only 

 obtained 5^ grains; but if about 2 per cent, of acetic, or of 

 some free malic, be added to the water, and finely divided 

 malate of lead be added, and the whole warmed by a water 

 bath, with constant stirring, the quantity of crystals will be 

 doubled for the same bulk of liquid. It is proper not to raise 

 the temperature higher than 160° Fahr. ; if boiled the salt 

 loses two or three atoms of its water of crystallization, and 

 then is quite insoluble in water hot or cold. The compo- 

 sition of malic acid is exactly the same as that of citric acid, 

 C 4 H 2 4 . 



