THE 

 LONDON, EDINBURGH and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FOURTH SERIES.] 



OCTOBER 1853. 



XXXVII. Reports on the Progress of the Physical Sciences. 

 By Dr. John Tyndall, F.R.S. 



On the Stereoscopic Combination of Colours, and on the Influence of Bright- 

 ness on the relative Intensity of different Colours. By H. W. Dove, 

 Berichte der Akademie, May 1851, and February 1852. 



IN the July Number of this Journal for 1851 we gave a de- 

 scription of several forms of the stereoscope invented and 

 applied by Professor Dove. The inquiries in which these inven- 

 tions originated have been since followed up by the learned Pro- 

 fessor ; and as they have reference to an application of this beau- 

 tiful, and now highly popular instrument, which has not as yet 

 been treated by its ingenious inventor, M'e propose placing the 

 results, in a condensed form, before the readers of the Philo- 

 sophical Magazine. 



]\I. Dove's reseai'ches have reference chiefly to the stereoscopic 

 combination of colours. In 184'1 he showed that the stereo- 

 scopic combination of the complementary colours of polarized 

 rays produced white light. He now makes use of drawings with 

 coloured outlines, the colours being either dioptric or catoptric : 

 the former he obtains by making drawings of white lines upon a 

 black ground, and viewing the stereoscopic combination through 

 a coloured glass ; in the second case, the figures are drawn upon 

 white paper in the colours which are intended for combination. 



The projection of a convex pyramid was drawn in red lines 

 upon a white ground, and on the same base the pi'ojection of a 

 concave pyramid in blue lines. On a second leaf the corre- 

 sponding drawings were made in the same coloui's for the other 

 eye. If, on viewing these drawings in the stereoscope, each pair 

 combined in the usual manner, we should have a convex red 

 pyramid and a concave blue pyramid, the axes of both forming 



Phil. Mag. S. 4. Vol. 4. No. 25. Oct. 1852. R 



