Chemistry and Physics. 347 



Liebig's condenser. An ordinary round bottom flask, placed by- 

 its side, is closed with a cork through which passes the stem of a 

 tap-funnel and also a delivery tube. By means of a thick rubber 

 tube, the end of this delivery tube is connected to the end of 

 a similar tube passing through the cork of one of the legs of the 

 U tube and terminating at its lowest part. Through a cork clos- 

 ing the other opening of the U tube, the thermometer passes. 

 This reads to hundredths of a degree. The flask is surrounded 

 with a tin plate vessel and the U tube with a box made of asbes- 

 tus cardboard. To make an observation, the delivery tube is 

 fixed in the U tube, and the bent portion of this tube is filled 

 with glass beads. The solvent is now introduced till it rises 3 or 

 4 em above the beads, and the thermometer is put in place. The 

 flask, half filled with the same solvent, is then connected with 

 the delivery tube and both it and the boiling vessel are heated 

 by carefully regulated lamps. When the liquid in both vessels 

 begins to boil, the tap in the funnel is closed and that connecting 

 with the condenser is opened, and the boiling is continued for 

 fifteen minutes or more. Then the thermometer is read by 

 means of a telescope. The substance is introduced into the boil- 

 ing tube by removing the thermometer, and the boiling point of 

 the solution is determined again in the same manner. The ther- 

 mometer used by the author read to hundredths, but by the tele- 

 scope thousandths of a degree could be estimated. The device of 

 the accessory flask enables the temperature to be made constant 

 even to this limit. Results are given in which the solvents used 

 were water, alcohol, ether, and carbon disulphide; and in which 

 the substances dissolved were mercuric chloride, mannite, cane 

 sugar, acetanilide, salicylic acid, naphthalene, iodine and sulphur. 

 The molecular mass was calculated from the formula m = Bxg/A 

 in which m is the molecular mass sought, B a constant depend- 

 ing on the solvent, g the mass of the substance dissolved in 100 

 grams of the solvent, and A the observed rise of the boiling- 

 point. B has the value , 02T a / W, where T is the absolute tem- 

 perature and W the heat of vaporization of one gram of the sol- 

 vent. In the case of water B has the value 5-2, alcohol the value 

 11 •5, ether 2T0 and carbon disulphide 24*0. With respect to 

 iodine the author finds its molecular mass in CS 2 from 247 to 261, 

 and in ether from 255 to 261 ; thus confirming Beckmann's conclu- 

 sion that its molecular magnitude is the same in both solutions. 

 For sulphur in CS Q the author finds the values 252 to 254 ; also 

 confirming Beckmann as to the existence of a complex molecule 

 consisting of S 8 . — Jour. Chem. Soc, lxi, 989, December, 1892. 



G. F. B. 



2. On the color of the Jems. — An investigation has been made 

 by Ostwald on the absorption spectra of the solutions of several 

 series of colored salts not only by measuring the position of the 

 bands but also by photographing the whole spectrum. It appears 

 from the results obtained that the spectra of dilute solutions of 

 salts having the same colored ion are identical. In the case of 



