. and obtained
instead of 9,650, as in electrolysis. This is indeed 11 per cent too high, but the limits of error in Weiss’s experiments were in his judgment quite as large as this. K. Przibram worked on suspensions in air of five or six different substances, the radii varying from 200
to 600
, and though his results varied among themselves by as much as 100 per cent, his mean value came within 6 per cent of 9,650. Both of the last two observers took too few displacements on a given drop to obtain a reliable mean displacement, but they used so many drops that their mean
still has some significance.