318 Scientific Intelligence. 



the bulb, there was immediate and rapid action in the cold, the 

 chlorine and bromine being absorbed very soon, the iodine more 

 slowly. Hence the author concludes that the action between 

 chlorine, bromine and iodine on the one hand and mercury on the 

 other does not depend on the presence of water vapor. Addi- 

 tional experiments were made to determine the effect of the silent 

 discharge and of direct sunlight upon highly purified chlorine, 

 but with negative results. — J. Chem. JSoc, lxxi, 47 1, May, 1897. 



G. F. B. 



2. On the Liquefaction of Fluorine. — From the properties of 

 the known compounds of fluorine, the conclusion readily follows 

 that fluorine itself can be liquefied only with great difficulty. 

 Advantage was taken therefore of the lecture upon fluorine given 

 by Moissan at the Royal Institution in May, to combine the ap- 

 paratus for its manufacture which he had brought from Paris, 

 with the unequalled facilities possessed by Dewae at the Institu- 

 tion, for producing low temperatures, in order to attempt its 

 liquefaction, the results of which are given in a joint paper. The 

 fluorine was prepared by the electrolysis of potassium fluoride 

 dissolved in anhydrous hydrofluoric acid. The fluorine gas was 

 freed from the vapors of hydrofluoric acid by means of a bath of 

 alcohol and solid carbon dioxide. The liquefying apparatus con- 

 sisted of a small cylinder of thin glass having a platinum tube 

 fused into its upper portion, within which was a second tube also 

 of platinum. The gas entered through the annular space between 

 the tubes, passed into the glass envelope and escaped through the 

 inner tube. Liquid oxygen was used as the refrigerant, several 

 liters of it being required. The apparatus being cooled down to 

 the temperature of quietly boiling liquid oxygen (—183°), the 

 current of fluorine gas passed through it without liquefaction 

 and without attacking the glass at this low temperature. On 

 making a vacuum above the oxygen, a rapid ebullition took 

 place and a liquid collected upon the interior of the glass envelope, 

 no gas now escaping from the tube. On closing this tube with 

 the finger, the glass bulb soon became filled with a clear and 

 very mobile yellow liquid, having the same color as the gas in a 

 stratum one meter thick. Hence fluorine liquefies at about — 185°. 

 On removing the apparatus from the bath of liquid oxygen, the 

 temperature rose and the liquid fluorine began to boil, evolving 

 abundance of the gas. Experiments were made upon the action of 

 this gas upon substances cooled to very low temperatures. Sili- 

 con, boron, carbon, sulphur, phosphorus and reduced iron, cooled 

 in liquid oxygen, did not become incandescent when placed in an 

 atmosphere of fluorine. Nor at this temperature did fluorine dis- 

 place iodine from iodides. But it still decomposed benzene and 

 turpentine with incandescence at 180°. When a current of fluor- 

 ine gas is passed through liquid oxygen a white flocculent precipi- 

 tate is rapidly formed. This thrown on a filter deflagrates 

 violently as the temperature rises. — G. i?., cxxiv, 1202, May, 

 1897; Chem. News, lxxv, 277, June, 1897. G. r. b. 



