540 Scientific Intelligence. 



cases is always from an even to an odd, or from an odd to an 

 even numbered family. It is to be observed that these changes 

 are in a direction opposite to the a-particle changes, and that two 

 of them are required for a return to the original family. 



A systematic investigation of the chemical nature of as many 

 of the radio-elements as possible has been made in Soddy's labo- 

 ratory by Alexander Fleck, with the result that it is now possible 

 to state or to predict the chemical nature of every known member 

 of the disintegration series. Soddy has constructed a diagram of 

 these changes which is here reproduced. He says that these 

 results prove that almost every vacant place in the periodic table 

 between thallium (204) and uranium (238) is crowded with non- 

 separable elements of atomic weights varying several units, and 

 this leads inevitably to the presumption that the same may be true 

 in other parts of the table. It may be predicted that all the end 

 products, probably six in number, of the three series, with calcu- 

 lated atomic weights varying from 210 to 206 should be non- 

 separable from lead, that is, that they should be lead, for which 

 the atomic weight 207 # 1 is now accepted. Nothing further is 

 necessary to explain the failure to obtain numerical relations 

 between the atomic weights, for, accepting this idea, we may 

 consider the elements to be composed of atoms of varying 

 weights of which our atomic weights are averages. It should be 

 observed that the non-separable elements appear to show no dif- 

 ferences in their spectra. Soddy suggests the desirability of 

 testing the constancy of the atomic weight of lead from a variety 

 of radio-active minerals. — Chem. JVews, cvii, 97. h. l. w. 



2. Determination of Alkalies in Rocks. — Y. Krishnayya has 

 described a modification of the usual hydrofluoric acid method 

 for the determination of potassium and sodium in rocks, which 

 appears to be a decided improvement. He decomposes the 

 material with hydrofluoric and sulphuric acids and evaporates off 

 both of the acids. The residue is boiled with hydrochloric acid 

 and if any insoluble matter is found it is filtered off and the treat- 

 ment is repeated. The whole solution is then made up to a 

 definite volume and a portion of the liquid corresponding to 1 g. 

 of the mineral is evaporated to dryness in a platinum dish which 

 is then ignited over a free flame until fumes of sulphuric acid 

 cease to come off. As the alkalies are in the form of sulphates 

 there is no danger of loss by volatilization. The residue, which 

 comes away easily from the dish and can be readily broken up 

 with a glass rod, is boiled for a minute or tw r o with a little water, 

 and, without filtering, a precipitation is made with barium chlo- 

 ride and an excess of barium hydroxide. After filtering and 

 washing, the solution is treated in the usual way, barium being 

 removed by ammonium carbonate, and the alkalies are weighed 

 together as chlorides. Two test analyses are given which show 

 very satisfactory results. The process appears to be no more 

 laborious than the method of J. Lawrence Smith, while it has the 

 advantage that the complete decomposition of the mineral may 

 be assured. — Chem. News, cvii, 100. h. l. w. 



