472 Intelligence and Miscellaneous Articles, 



Caustic potash at a temperature above 392° F. acts strongly on 

 pectic acid, and Gay-Lussac has remarked that much oxalic acid is 

 formed. Pectic acid dried at 284° F. yielded by analysis 



Hydrogen 4'71 



Carbon 43-21 



Oxygen 52-08—100. 



Journal de Pharmacle, 24, 201. 



PECTATES OF POTASH, SODA, AND AMMONIA. 



M. Regnault states that pectic acid combines very perfectly with 

 bases, and in general forms gelatinous compounds. The pectates of 

 potash, soda and ammonia are alone soluble in water ; all others are 

 insoluble and form transparent jellies, more bulky and firm than the 

 acid itself, and they may be pressed through a cloth when they have 

 been precipitated from cold solutions ; when precipitated hot they 

 are not firm, but are like the acid itself. 



It is extremely difficult, and perhaps even impossible, to obtain 

 the pectates in a state of determinate saturation ; all effbrts to obtain 

 them failed. This difficulty is derived from the impossibiHty of always 

 procuring definite soluble pectates. 



If a solution of potash be digested with an excess of gelatinous 

 pectic acid, it dissolves in large quantity, the liquor loses its alkaline 

 reaction, and after a certain time, it even becomes slightly acid, 

 evidently owing to an excess of the acid. If alcohol be added to a 

 solution of pectate of potash or soda, a gelatinous precipitate is 

 formed, which appears to be a sub-pectate. This jelly when washed 

 with alcohol loses alkali, andprobably becomes neutral pectate, when 

 the washing is sufficient ; but it is difficult to determine the exact 

 point. 



Neutral pectate of ammonia is not obtained more readily ; if pectic 

 acid be dissolved in excess of ammonia, a solution is obtained, which 

 by long boiHng becomes acid to test paper ; this when evaporated 

 in vacuo leaves a transparent mass, which when dissolved in water 

 has also an acid reaction ; in both these cases, we obtain a pectate 

 with excess of acid. The insoluble pectates leave very hard horny 

 masses, and which it is extremely difficult to powder ; it is therefore 

 also very difficult to burn them with oxide of copper. To obtain 

 the comlDustion perfectly, it is necessary to put a certain quantity of 

 chlorate of potash mixed with oxide of copper at the bottom of the 

 tube. 



When heated in contact with the air, dry pectates take fire, and 

 continue to burn till all the organic matter is destroyed. The pec- 

 tates retain the last portions of water with considerable force ; tiiey 

 must be heated to 284° or 302° F. to render them perfectly dry; they 

 do not begin to decompose till heated to about 392° ; the dry pectates 

 are very hygrometric ; when they are to be analysed they must be 

 quickly weighed, and dried afterwards in the combustion tube, and 

 kept at a temperature near 212°. — Ibid. 



