244- Intelligence and Miscellaneous Articles. 



Richard Sheepshanks, M.A. ; Lieutenant William S.Stratford, R.N.j 

 Edward Troughton, Esq. F.R.S. L. & E. 



XL VI. IntelligeJice and Miscellaneous Articles. 



PREPARATION OF CAUSTIC POTASH. BY M. LIEBIK. 



IF one part of carbonate of potash be dissolved in four parts of 

 water, and the solution be boiled with slaked lime, the potash does 

 not lose the smallest quantity of carbonic acid ; it does not become 

 caustic, even though lime be added to any extent, or however long 

 the boiling may be continued. If, however, 6 parts of water be 

 gradually added to the above mixture, it will be found, and without 

 further boiling, that the potash loses its carbonic acid gradually ; and 

 that after the addition of the last portion of water, the potash is per- 

 fectly caustic. If the water be added at once, the potash becomes 

 very quickly caustic. 



This peculiarity is explained by the fact, that concentrated caustic 

 potash takes carbonic acid from lime. This fact is readily proved by 

 boiling powdered chalk with concentrated potash, entirely free from 

 carbonic acid 3 the solution added to muriatic acid occasions brisk 

 effervescence. M. Liebig states that the carbonate of potash which 

 is to be made caustic should be dissolved in at least 1 parts of water. 

 Ann. de Chim. et de Pliys. xlix. p. 142. 



ANALYSIS OF GUMS. 



M. Guerin has analysed several varieties of gum with the annexed 

 results. Arabin, which constitutes the greater portion of gum arabic, 

 is composed of 



Carbon 43-81 



Oxygen 49*85 



Hydrogen 620 



Azote 14 



10000 

 The azote is considered as non-essential. 

 Gum arable was found to consist of 



Arabin 79'40 



Water 17-60 



Ashes 3-00 



100-00 

 Messrs. Gay-Lussac and Thenard found its composition to be : 



Arabin 84-16 



Water 13-43 



Ashes 2-41 



100 00 

 The difference of water found depended upon the different methods 



