APPENDIX. 



383 



FOLIN'S FUME-ABSORBER. 



Since the fumes arising from the incineration of a substance with boiling 

 sulphuric acid are extremely irritating, that operation should be conducted in 

 a fume chamber or under a hood. But it is preferable to use the very con- 

 venient apparatus devised by Folin, since the removal of the condensation 

 water materially accelerates the incineration. 



Fig. 51. Folin's fume-absorber. 



The apparatus consists of a bulb C (i inches in diameter) blown into a 

 piece of fths. tubing. The lower end has blown into it an open piece of 

 narrow tubing 2^ inches in length. The bulb rests on the neck of the flask or 

 test-tube in which the incineration is conducted. To the upper end of the 

 tube is fixed a piece of narrow glass tubing which is bent at a convenient angle 

 and connected by a short length of rubber tubing to a glass tube B. This is of 

 such a size that it just slips into one limb (A) of a T-piece. This is fastened to 

 a board or shelf by metal clips. One end of the horizontal limb of the T-piece 

 is connected to a suction pump, the other end being joined by a piece of pressure 

 tubing (D) and a length of metal tubing (E) to another T-piece. This can be 

 connected to another fume-absorber. One good pump is sufficient for 3 

 absorbers. Those not in use should be stoppered with corks. It is sometimes 

 necessary to fit a rubber collar on to B, so that good suction is obtained through 

 C. Owing to the rubber joints the angles of the limbs A and F can be varied 

 to suit the heights of the vessels in which the incineration is being conducted. 



The fumes are carried over by the air current into the pump, a wash bottle 

 containing soda being interposed to prevent damage. The condensation 

 water collects in the pocket below C and can be removed by inverting the 

 fume-absorber at the end of the operation. 



By inverting a funnel over an evaporating basin, and arranging the 

 apparatus so that the end of the funnel fits loosely into the neck of the absorber, 

 the fumes from boiling nitric acid can be carried off. 



