Chapter I: Preparation of Reagents 



11 



20. Canada Balsam. Dry 2 grams of Canada balsam on a 

 sand bath, or in a warm chamber until it becomes hard (1 to 2 

 hours at 65C.). Do not overheat. When cool add enough xylol 

 to make a thin, syrupy fluid. Roll a sheet of paper into a cone to 

 serve as a funnel, and filter the fluid through absorbent cotton. 



FIG. 24. The Lillie Water-Bath. 



The bath consists of a large chamber containing a series of drawers of equal size, 

 250mm. long, 100mm. wide, 80 mm. deep. Each drawer has copper front and bottom ; the 

 sides and back are perforated zinc, thus securing free circulation of warm air. The drawers 

 are separated by perforated cross partitions and run on slides free from the lateral supports, 

 thus permitting sufficient circulation of warm air to secure equal temperature in the top 

 and bottom of the bath. Water gauge and tubulatures for gas regulator and thermometer 

 are provided. This bath is especially adapted to class work, since each student may carry 

 on his work in a separate drawer. 



Thicken the solution slightly by leaving the cap off the bottle in 

 a place free from dust, and allowing some of the xylol to evaporate. 

 Or, fill your balsam bottle one-third full of the liquid xylol- 

 balsam now on the market, and dilute to the proper consistency. 



