88] The Soda Lime Process 59 



88. The Operation. — First find a cork to fit the iron 

 tube. Bore a hole through it large enough to take the end of 

 the Will and Varrentrap bulb tube. Fix it as shown in fig. 26. 

 Now run into the bulb 20 c.c. of the seminormal acid from a 

 burette (d, fig. 25) and set it on one side. 



Next weigh out accurately about -3 gram of pure dry urea. 

 Place the iron tubes in the staple fixed in the drawer, just as 

 the tube stands in fig. 25. 

 By means of the copper 

 funnel introduce sufficient 

 of the soda lime and sugar 

 mixture to fill an inch at 

 the end of the tube. Pour 

 as much granulated soda 



° Fig. 26. 



lime as could be held on a 



penny into the mortar. Turn out the urea on to this, and just 

 cover it with finely powdered soda lime. Then add about 

 twice as much granulated soda lime as is already in the 

 mortar, placing it first on the watch glass and pouring it thence 

 into the mortar. This ensures that all the urea shall be re- 

 moved from the glass. Now mix thoroughly with the steel 

 spatula, and pour through the funnel into the tube. Rinse 

 out the mortar with fresh granulated soda lime several times, 

 pouring the rinsings into the tube, stopping when it is within 

 4 inches of the open end. Cover the soda lime with a plug 

 of asbestos which fills about an inch of the tube when gently 

 pressed down with a thick glass rod. Now close the tube 

 with the cork through which passes the tube of the Will and 

 Varrentrap bulb. 



The tube is now ready for heating, which may conveniently 

 be done in a Bunsen combustion furnace, as shown in fig. 27, 

 but any tube furnace may be used. (A few of the tiles have 

 here been removed to show the construction of the furnace.) 



