LARD AND LARD ADULTERATIONS. 



431 



to use tbe ordinary balance for this method for temperatures near the 

 boiling point on account of the difficulty of conducting the condensed 

 vapors out of the balance case. For our work, therefore, we have used 

 this balance only for lower temperatures. 



FIG. 18. 



DESCRIPTION OF INSTRUMENT. 



The Mohr or Westphal balance is well illustrated in the figure. The 

 position of the instrument is shown in equilibrium. The bob is fur- 

 nished with a delicate thermometer. If the bob be graduated for the 

 displacement of exactly 5 grams of distilled water at 35, for instance, 

 a deep red line indicates that point. The weights are determined on 

 the principle of the ordinary rider. There is one weight for the 5 

 grams and one for each 5 of decimal places of the under gram weight. 

 The beam is so adjusted as to be in exact equilibrium when the dry bob 

 is suspended in air. It is divided into ten parts. The big weight counts 

 5 when placed directly over the suspension point of the bob; 4.5 when 

 placed at 9; 4.0 when placed at 8, etc.; when a lighter weight falls 



