British Association for the Advancement of Science. 299 



By Dr. Proiit's analysis, starch sugar is C ^H"'0' *, or it con- 

 tains an atom of water more than diabetic sugar. 



Mr. Robert Mallet read a communication on a neiu case of the 

 decoloration of recent solutions of Caustic Potassa of commerce, 

 and on the nature of the coloring matter. The author stated, 

 that the caustic potassa of commerce, was well known to be a 

 very impure compound, containing besides potassa, sulphate of 

 potassa, chlorides of potassium and iron, peroxide and carbonate 

 of iron, silex, charcoal, and generally lime. He had also in one 

 case found a trace of cobalt, and in several protoxide of lead, 

 probably from the vessels used in its preparation. The color of 

 recent solutions of this potassa in water freed from air by boiling, 

 is apple-green, and occasionally, purplish-green, which, whether 

 exposed to air or not, or in dark or light, gradually disappears, 

 leaving the solution colorless. A red precipitate of peroxide and 

 carbonate of iron is produced on solution ; but, after a time, the 

 green solution in losing color, deposits a second in very small 

 quantity, which Mr. M. has found, by analysis, to consist of, 

 Sesquichloride of iron, - . - - - 15.7 

 Sesquioxide of iron, _ _ _ _ 83.2 



The decoloration of the solutions of common caustic potassa 

 was effected by violet-colored light in 30 hours, and by red in 

 200 hours. 



Mr. H. Pattinson gave an account of a new process, by him 

 discovered, for the extractio7i of Silver from Lead. By this pro- 

 cess, the details of which are too extensive for insertion here, a 

 large amount of both lead and silver wasted by the methods now 

 employed, would be saved. 



Dr. Golding Bird communicated "Observations on some of the 

 Products of the action of nitric add on AlcohoV^ Numerous ex- 

 periments are related in this paper, and the following are some of 

 the author's conclusions. 1. During the action of nitric acid on 

 alcohol, no oxalic acid is formed as long as nitrous ether alone 

 distils over. 2. Aldehyd is not produced, in any appreciable 

 quantity, until oxalic acid appears in the retort, and the produc- 

 tion of nitrous ether nearly ceases. 3. During the preparation of 

 nitrous ether in the cold, acetic acid is abundantly produced, and 

 appears to replace the oxalhydric acid formed when heat is em- 

 ployed. 



