1899 1/2d (10) and 2d (2) Colour trials, perf 121/2 on watermarked gummed paper, all pen cancelled in various colours or with Melbourne (JY 14) trial datestamps (2), then treated with various chemicals by the government analyst, Mr C.W Blackett, to test the reaction of the cancelling inks and of the actual stamps. Three with pieces torn away and one severely stained by the chemicals, the others all reasonable appearance, an interesting and unique group. (12). Photo on Page 140. (Image1)