Chemistry and Physics. 567 



at least hundreds of thousands of years. The facts thus found 

 lead to the view that the porous structure of the aut unite, in 

 comparison with the dense oxides, has allowed the escape of helium, 

 aud also the leaching out of the lead and a part of the radium. 

 From a consideration of this and other minerals it appears that 

 lead is more easily removed than is radium. — Berichte, xliv, 771. 



h. l. w. 



2. The Determination of Cane Sugar in the Presence of other 

 Sugars. — Adolf Jolles has devised a new and very simple 

 method for the determination of saccharose when other sugars 

 are present. He finds that the other sugars, such as dextrose, 

 levulose, maltose, mannose, galactose, arabinose, lactose, and 

 rhamnose are readily decomposed by the action of dilute sodium 

 hydroxide solution, while the saccharose may be left undecom- 

 posed and may then be determined by the polariscope. A one- 

 tenth normal solution of sodium hydroxide is recommended, in 

 which the cane sugar may be present in any convenient amount, 

 but the contents of dextrose, levulose, invert-sugar, etc., should 

 not exceed 2 per cent. The treatment may consist in boiling the 

 liquid for three quarters of an hour in connection with an inverted 

 condenser, or the liquid may be placed in a pressure-flask or sealed 

 tube and heated in boiling water for the same length of time, or 

 finally the solution may be allowed to stand in a closed flask at 

 37° 0. for 24 hours. The last treatment is preferred for exact 

 work because it gives a minimal amount of discolorization, but 

 the other methods give reliable results, and colored liquids may 

 be treated with basic lead acetate. It seems probable that the 

 method will be very useful in connection with food-analysis, 

 etc. — Monatshefte, xxxii, 1. h. l. w. 



3. The Action of Sulphur Dioxide iqoon Ammonia. — The 

 products of the reaction of these common gases have been fre- 

 quently studied, and it seems remarkable that they have not been 

 fully explained, but it appears from the recent work of Ephraim 

 and Piotkowski that such is not the case. These investigators 

 have found that there are three different compounds formed instead 

 of two as has previously been supposed. With an excess of sul- 

 phur dioxide, amido-sulphinic acid, NH 2 .S0. 2 .H is produced, while 

 with an excess of ammonia, according to the temperature, there 

 may be formed either the ammonium salt of the above acid, 

 ammonium amido-sulphite, NH 2 .S0 2 .NH 4 , which is white, or a red 

 compound having the same empirical formula as the last, but 

 with double its molecular weight. This has been found to be the 

 tri-ammonium salt of imido-sulphuric acid, having the formula 



(Nil )N<Cor) 2 /-NjTj' 1 \- This constitution was established by finding 



that one-quarter of the nitrogen was differently combined from 

 the other three-fourths, so that at least four nitrogens must be 

 present in it. By proper treatment it gives a silver salt, 



-A-gN^iSO^Aa-' which is rather unstable. — Berichte, xliv, 379. 



H. L. W. 



