Intelligence and Miscellaneous Articles. 547 



If the wires of the pole (which should be rather thick) be placed 

 about five millimetres apart, and the intervening space be blown upon 

 rather strongly with a bellows, the greenish-yellow atmosphere is 

 seen to be drawn towards the opposite side, where it forms a large 

 flame of a violet colour. It may also be blown along the wires of 

 the pole, and it is then seen to be furrowed by a number of very 

 sinuous, more or less white jets of fire, which are usually disposed 

 in strata. The violet light appears to be circumscribed by two 

 bundles of violet rays, which rise from the points of the poles and 

 unite in irregular curves, like those of a flame driven by the wind. 

 The true spark does not appear to be affected by the current of air. 

 — Comptes Rendus, Feb. 5, 1855, p. 313. 



ON COMPLEMENTARY COLOURS. BY H. MEYER. 



Without going into the consideration of the proposed explana- 

 tions of the complementary colours, I give a few experiments by 

 which the observation of these subjective colours is much facilitated, 

 reserving a further consideration of these phsenomena, and the con- 

 clusions to be drawn from them, for a subsequent memoir. 



If a narrow strip of gray paper be laid upon a coloured surface, 

 this strip appears tinged with the complementary colour of the body 

 on which it is lying. This experiment does not, however, always 

 succeed equally well, and is best performed with a green surface ; if 

 the strip of paper be white and a little broader, the complementary 

 colour is only observed after long watching, or perhaps not at all. 

 The complementary colour may, however, be produced immediately 

 and quite distinctly, even with white strips of such breadth, that, 

 without further assistance, they cannot show the complementary 

 colour (several inches broad) by laying a leaf of fine, transparent 

 writing-paper over the coloured surface and white paper. The white 

 strip immediately appears covered with a tolerably uniform pale tinge 

 of the complementary colour. 



A sheet of coloured paper laid beside one of white paper does not 

 allow the complementary colour to be observed upon the latter ; and 

 it is only when the coloured sheet has been looked at for some time, 

 and the eyes are then alternately directed from the coloured surface 

 to the white, that the strip of the latter lying next to the coloured 

 surface is tinged with a somewhat intense complementary colour. 

 But if a transparent sheet of writing-paper be laid over the coloured 

 and white surfaces, the complementary colour immediately makes its 

 appearance upon the latter, without any previous removal of the eye 

 from one surface to the other. If the eye be directed to the margin 

 of the white and coloured surfaces, the portion of the white surface 

 lying next to the coloured surface appears more intensely tinged with 

 the complementary colour than the parts lying at a greater distance ; 

 but if the white surface be examined by moving the eye, so that the 

 different parts of the white surface may be represented one after the 

 other upon the same part of the retina, the surface appears covered 

 with a more uniform tint of the complementary colour. — Poggen- 

 dorff's Annalen, vol. xcv. p. 170. 



