DEFINITE FIGURES BY THE DEPOSITION OF DUST. 
195 
cases, a considerable amount of deposit was formed, commencing at an appreciable 
distance from the pin. The pin was tlien lowered, so that the edge was immediately 
below the plate ; when it was 2 millims. helow, it produced a considerable amount 
of deposit j when 4 nnlhms. below, the amount was much diminished, and when 
8 millims., only a trace of deposit was formed. Tt was found tliat as the pin 
Fig. 28. Fig. 29. 
receded, so did the deposit recede from the edge ot the plate, hecoming at the same 
time smaller in amount. 
Fig. 27 shows the deposit formed when the pin was 3 millims. away, and still at the 
level of the plate. Fig. 28 is the figure formed when the pin was 6 millims. from the 
2 C 2 
