MR. W. CROOKES ON REPULSION RESULTING FROM RADIATION. 
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direct proportion to the number of candles (149). This law is somewhat interfered 
with at close quarters by the heating of the bulb and fly when extra candles are 
brought near ; but for such an experiment, in which great accuracy cannot be expected, 
and which is only of illustrative interest, the figures given are near enough. 
Fig. 28 shows the curve plotted from these observations, using the first and fourth 
Fig. 28. 
columns, and omitting the observations at 577 and 400 millionths of an atmosphere, 
so as not unduly to extend the diagram. The curve traced through the dots 
representing observations, illustrates the gradual increase of sensitiveness up to a 
certain point of rarefaction, and the sudden drop after that point is reached. 
