e please. ‘ 
__ It should be observed that air bubbles carried by the drop into 
the liquid produce an irregular motion, destructive of the desired 
fect. Hence the beak should be placed only a short pres 
above the surface. An interval not exceeding one and a hal 
the reservoir as motionless as possible, its mass 
the n is allowed to impinge upon it. 
Q ing with these precautions, and viewing the res 
point a little lower than the level of the 
soon after merging in the liquid, 
n 
