34 J' SAIiURAI: MODIFIOATIO-X OF BECKMANX'S BOILTXG 



connecting' the delivery tul^e d from the tul^e e, a small quantity of a 

 concentrated solution of the substance, made beforehand, is introduced 

 into the boilino- vessel bv means of a small funnel attached to the 

 india-rubl'Cr tubing /. After removing the funnel, communication is 

 rc-estabbshcd between the boiler and the boiling vessel. 



Tjie lam];s, which have been put aside but not blown out, are 

 next brought under the two vessels as before, and the boiling point of 

 the solulion determined in exactly the same manner and under 

 exactly the same conditions as those in which the boiling point of the 

 solvent was determined, collecting, of course, the same quantity of the 

 distillate. When the exact temperature has been ascertained, the 

 lamps are put out, the stop-cock r opened, the stop- cock s closed, and 

 the whole apparatus allowed to cool. 



After the solution has completely co()led, the percentage composi- 

 tion of the solution is determined ])v transferrin 2: some of the solution 

 into a weighed stoppered ])ottle ]>y means of a pipette and, after 

 ascertaining the weight of the solaii(3n taken, evaporating the latter 

 at a o'entle heat on a water l)alh and weijihin*:'' the fixed residue. In 

 case of iodine, it is determined vojumeti'lcally by a standard solution 

 of sodium thiosulphate. 



From the account above detailed of the process I adopt, it will ])e 

 seen that it differs from the method used In' Beckmann essentially in 

 this that, whilst Beckmann takes a weighed quaiitity 1)oth of the 

 solvent and of the solid substance, arid determines tlie boiling p(;ints 

 in an apparatus provided with a reflux coîidenser and, therefvre, 

 requires a complicated arrangement, the meth(-d liere de; criljed re<[uires 

 no special apparatus, as it determines ihe boihug poiiits in the 

 ordinary manner, l)ut o1)viatirjg the u,^n:d (liflicubies. of such det(>r- 

 minations and, at the same time, kee])iiig llie (jiiaiiiity of the boiliiig 

 liquid constant, b}^ ])a,-siiig a current of tlie \a])v>ur of tlie solvent 



