Brass Strong Fairly good Toolsteel Barely perceptible Very feeble Zinc None Very strong Aluminum Very strong None Copper None Fairly strong but much less than zinc Lead None Very strong but a little weaker than zinc Silver Strong, a thin plate Weaker than copper being used Tin None Very strong about like lead Nickel None About like copper Lead-glass Very strong Feeble Mica Very strong Very strong about like lead Ebonite Strong About like copper. By comparing, as in previous experiments, the intensity of the photographic impression by reflected rays with an equivalent impression due to a direct exposure of the same bulb and at the same distance, that is, by calculations from the times of exposure under assumption that the action upon the plate was proportionate to the time, the following approximate results were obtained: Impression Reflecting by Impression Body Direct by Action Reflected Rays. Brass 100 2 Tool steel 100 0.5 Zinc 100 3 Aluminum 100 0 Copper 100 2 Lead 100 2.5 Silver 100 1.75 Tin 100 2.5 Nickel 100 2 Lead-glass 100 1 Mica 100 2.5 Ebonite 100 2 He stated that while these figures can be but rough approximations, there is, nevertheless a fair probability that they are correct, in so far as the relative values of the sciagraphic impressions of the various objects by reflected rays are concerned.