TRANSACTIO'S OF SECTIOjS B. 609 



4. Some Experiments on the Molecular Refraction of Dissolved Electrolytes, 

 By Dr. J. H. Gladstoxb, F.B.S.,and W. Hibbert. 



This was a preliminary notice of some experiments undertaken in the hope of 

 throwing some further light on the nature of electrolytes in solution, and especially 

 on the views advocated by Van t'Hoff, Ostwald, and Arrhenius. 



It was discovered many years ago that hydrochloric acid had an increased 

 molecular refraction when it was dissolved in water, and it has been more recently 

 observed that this increase has further augmented as the solution is made weaker. 

 It was now found that on raising the temperature 55° there is a distinct reduction 

 of the molecular refraction. This is scarcely what would be expected from an 

 increase of ionic dissociation. It would appear that chloride of lithium follows the 

 same law as hydrochloric acid in regard to the effect of dilution, but on raising the 

 temperature it was found that the molecular refraction was slightly increased in 

 strong solutions, but decidedly decreased in weak ones. Chloride of sodium shows 

 much the same molecular rel'ractionat different strengths and in different tempera- 

 tures. Sulphate of magnesium was examined as a salt of a different type, but it 

 closely resembled the sodium chloride. As the results obtained from these four 

 electrolytes were so diverse no general conclusions were drawn. 



5. The Action of Seat on Alkaline Hypochlorites. By Professor H. M. 

 McLeod, F.E.8. 



6, A Simple Apparatus for Storing Dry Gases. By W. Symons, F.C.S. 



Requiring some dry carbonic acid gas and ammonia, with only very limited ap- 

 pliances at hand, the author was at a loss how to store them. A mercurial trough 

 was out of the question. Ordinary petroleum as sold in the oil shops suggested 

 itself. For this purpose a large wide-mouth bottle had inserted into its cork a 

 short delivery tube with a tap, and a metal funnel, with a long metal tube 

 reaching nearly to the bottom of the bottle, also with a tap below the funnel. 

 This is to supply the petroleum. To increase the pressure the tube should be long 

 enough above the bottle. A glass tube, open both ends, is inserted in the cork, as 

 large as it can be, say f-inch internal diameter, or more. This reaches to about 

 half an inch from the bottom of the bottle. AVith the cork well secured by 

 cement or varnish not acted on by petroleum, the bottle can be filled with petro- 

 leum through the funnel, both taps being open. When full they are closed. A 

 glass siphon, with one end turned up and the other end a little enlarged to facili- 

 tate filling it with petroleum, is then inserted in the large tube, the finger being 

 kept on the' enlarged end so as to retain the petroleum while inserting it. If the 

 whole be air-tight no petroleum will escape, and this will test the gasholder. 

 Another tube, with the bottom turned, also fits into the large tube, and the bent 

 end must be kept outside it, in the bottom of the bottle, so as to deliver the gas 

 into the bottle. To the upper end of this tube is attached, by india-rubber 

 tubing, the gas-generating apparatus, but with a small Woulfe's bottle intervening 

 as a safely bottle to catch any petroleum which may be drawn over by any irregu- 

 larity in generating the gas. Of course, the gas must also be passed through a 

 drying apparatus. When sufficient gas has been collected, both tubes are with- 

 drawn, and the gas stored for use. When required, petroleum must be put in the 

 fuimel, and the supply regulated by the tap. If the gas is to be stored for some 

 time the siphon should remain in the gasholder, and the outer end of it be put into 

 a bottle partially filled with petroleum to provide for the expansion or contraction 

 of the gaa by variations of temperature or atmospheric pressure. 



1891. 



