14 COMPiRATlVE EXAMINATION OF MUCOUS ACID, 



a certain degree, it is manifested by a spark darting from 

 one to the other, and the equiHhrinm is thus restored. 



1 cannot but consider the fixation of this point, after 

 many controversies, as being no less conducive to the 

 advance of our knowledge in the maze of terrestrial causes, 

 than the determinations concerning air and the cause of 

 heat ; and no experiments and observations appear to ni« to 

 deserve more tlie joint endeavours of experimental philoso- 

 phers, than those concerning the modifications of the 

 electric Jluid, in the atmosphere and in the ground, of 

 which, in my former paper, I have shown the great influ* 

 ence in terrestrial phenomena, 



Ashjieldf near Honiton, 

 12th October, 1810. 



II. 



Comparative Examination of the Mucous Acid formed hy the 

 Action of Nitric Acid on Gums and on Sugar of Milk. 

 By A. Laugier*. 



Lime in the IVJlR. VAUQUELIN, by his experiments on gu^ns 



^mmedinte arabic and tragacanth, has ascertained the existence of a 



principles of .... 



■regetables. considerable portion of lime in the immediate principles of 



vegetables. The reading of his paper suggested to me the 



following reflexions. 

 Whatbpcomes 1st, What becomes of the lime contained in these gums, 

 verdng cums"' ^^^^" they are treated with nitric acid, in order to obtain 

 into mucous the mucous acid ? ' 



**^ " 2dly, Does it not combine with the oxalic acid, which ia^ 



formed almost at the same time as the mucous ? 



3dly, As the oxalate of lime is more insoluble in water 



than the mucous acid, does it not fall down with this acid, 



when the residuum of the process is washed, and occasion 



a sensible alteration of its properties ? 



4thly, How may we ascertain the presence of oxalate of 



lime in the mucous acid obtained from gums, and separate 



X\\\^ calcareous i^alt from the acid, the purity of which it 



affects ? 



♦ Abridged from the Annal. de Chlm. vol, LXXII, p. 8i. 



T» 



