220 Intelligence and Miscellaneous Articles. 



1 1 . Potash does not dissolve mellon and yield the mellonide of 

 M. Gmelin, as stated by M. Liebig ; but it produces a tribasic salt 

 C (HM^) N^ O'-, containing hydrogen and oxygen, at the same time 

 that ammonia is developed. Other products are also formed at the 

 same time. 



12. Mellon does not simply and purely combine with potassium ; 

 but the combination occurs with the evolution of ammonia, and the 

 product is a bibasic salt C"^ N^ M^, a salt which on dissolving in water 

 probably gives C N*^ M- H^O, and appears to be identical with the 

 mellonides of M. Gmelin. 



13. Mellon does not integrally dissolve in sulphuric acid, for the li- 

 quid contains sulphate of ammonia. — Ann. de Ck. et de Phys., Jan^aer 

 1847. 



ON THE PREPARATION, PROPERTIES AND COMPOSITION OF 

 ACETAL. BY M. STAS. 



The author states that by following precisely the directions of M. 

 Liebig for preparing acetal, he obtained a product which, when re- 

 distilled, did not possess any fixed boiling-point. The liquid pro- 

 cured at 203° F. recommenced boiling at about 190°, and the tempe- 

 rature gradually increasing, finished at 226° or even 230°. 



The product distilled at 190° was reduced to about half by a con- 

 centrated solution of potash ; this action takes place in a few hours 

 without the contact of air. The portion collected at about 220°, and 

 below it, does not undergo any ajipreciable alteration by the alkaline 

 solution without the contact of the air. 



The potash solution, obtained by treating the first product, remains 

 colourless ; when saturated with carbonic acid and evaporated in 

 vacuo, a residue is left, which yields to anhydrous alcohol a white 

 salt, which is very soluble in water, and precipitates nitrate of silver 

 in pearly white laminae ; it is merely acetate of potash without any 

 trace of formiate. 



These facts prove, according to M. Stas, that the acetal described 

 by M. Liebig is a mixture of at least two substances, one of which 

 is acetic aether, and the other is acetal, properly so called, and com- 

 parable to the methylal of M. Malaguti, as will hereafter be shown. 



M. Stas observes that some chemists still doubting of the exist- 

 ence of acetal, he states the method of procuring it in a certain and 

 rapid manner, and constant in composition, before he describes its 

 properties ; the process is as follows : — 



Fragments of pumice-stone are to be washed with hydrochloric 

 acid and then heated to redness ; afterM'ards the pumice is to be 

 moistened with alcohol which is nearly anhydrous, and to be intro- 

 duced into a balloon capable of containing 80 to 100 pints. This 

 balloon should have a short neck, but large enough to allow of 

 introducing the arm. As many capsules as the balloon will contain 

 are to be placed on the pumice ; these capsules are to be as flat as 

 possible, and covered with a thin stratum of platina black. The 

 neck is to be perfectly covered with a glass plate, and the balloon is 



