Chemistry and Physics. 397 



denser for sulphuric acid. The side tube then turns down per- 

 pendicularly and is connected with a Volhard's flask (a conical 

 flask with a triple-bulb connected to it near the bottom). The 

 Volhard's flask is charged with an aqueous solution of silver 

 nitrate into which the delivery tube does not clip. To the 

 fractionating flask containing the substance is attached a drop- 

 ping funnel, the stem of which reaches nearly to the bottom of 

 the flask, by means of an ordinary cork, or better with a ground 

 glass connection, and by means of this 30 to 50°° of concentrated 

 sulphuric acid are delivered upon the substance. The acid is 

 gradually heated with aspiration of air through the apparatus 

 during the heating or at the end of the operation as occasion 

 may require. In cases where bromine or iodine are set free a 

 little filter paper or metallic copper is used with the substance in 

 order that enough sulphur dioxide may be produced to reduce 

 these substances. After the halogen acid or free halogen has 

 been distilled over, the liquid in the receiver containing the silver 

 halide as well as much silver sulphite is transferred to a beaker, 

 treated with considerable water and 50 cc of concentrated nitric 

 acid and heated gradually at first, and finally strongly. The 

 silver halide is collected and weighed as usual. — Chemiker 

 Zeitung, xxx, 167. h. l. w. 



3. The Distillation of Metals of the Iron Group. — Moissan" 

 has continued his investigations upon the boiling and distilla- 

 tion of metals, and finds that the metals of the iron family have 

 very different boiling points. Manganese is the most volatile of 

 all, and it distils easily at a lower temperature than lime. Next 

 comes nickel, which boils quietly ; then chromium, which distils 

 in a regular manner with a current of 500 amperes and 110 volts. 

 It is more difficult to boil iron, and before boiling takes place 

 there is a tumultuous disengagement of gas which the metal has 

 taken up, but with a current of 1000 amperes and 110 volts 400 s 

 of iron were distilled in 20 minutes. Uranium has a higher boil- 

 ing point than iron, while uranium and tungsten are still more 

 difficult to bring to boiling. The latter metal could only be 

 brought to regular ebullition by the use of a current of 800 

 amperes and 110 volts after an exposure of 20 minutes. — Comptes 

 JRendus, cxlii, 425. h. l. w. 



4. Atomic Weight of Radium. — The question as to whether 

 this atomic weight is 225 as determined by Mme. Curie by a 

 chemical method, or 258 as found by Runge and Precht from a 

 study of the spectrum, has been discussed by H. C. Jones. He 

 shows clearly that no valid objection can be raised to the higher 

 value on the ground of position in the periodic system, for the 

 higher number readily allows it to be placed in the group with 

 barium, but in a series below the one in which it would be placed 

 as 225. He prefers the higher atomic weight on the ground that 

 he believes that the greater the mass of the atom, the less is its 

 stability and consequently the greater is its radio-activity. This 

 view is contrary to Rutherford's conception of the transforma- 



