Bulletin. 



Vol. II, No. 8. 



NOVEMBER, 1903. 



( Whole Series, 

 ) Vol. XII, No. 8. 



SOME MOLECULAR WEIGHT DETERMINATIONS, 



USING A MODIFIED FORM OF BECKMANN'S BOILING- 

 POINT APPARATUS. 



BY HERBERT A. CLARK. 

 With plate VI. 



npHE following work was undertaken to test a modified form 

 of Beckmann's boiling-point apparatus, devised and made by 

 Dr. E. C. Franklin.^ The original intention was to determine 

 the molecular weights of several substances by the boiling-point 

 method, and to compare the results, as 

 well as the accuracy and convenience of 

 manipulation, with corresponding factors 

 for the ordinary Beckmann apparatus, and 

 also to confirm the observations of Frank- 

 lin and Kraus" that the height of the 

 liquid over the bulb of the thermometer 

 has a marked effect on the readings of this 

 instrument. 



The particular piece of apparatus used 

 in this work is represented by figure 1, 

 which is one-sixth natural size. It con- 

 sists essentially of a Dewar tube, A, with 

 a coil of fine platinum wire, B, in the bot- 

 tom, and a water-jacketed condenser, C, 

 leading up from the top. The side tube, 

 E, allows the insertion of a solute, or of 

 more of the solvent, without disturbing the Fig. i. 



1. Franklin and Kraus, Am. Chem. Jour., 20, 836 (1898). 



2. Am. Chem. Jour., 20, 839 (1898). 



(247) 



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