1898.] MICEOSCOPICAL JOURNAL. 199 



of my discovery consists in the fact that I have not tried 

 to see this image ! In fact, in all the articles that I have 

 published on this subject I have stated that I had dis- 

 covered how to make this image visible, and that I had 

 succeeded in getting a magnification beyond that of 

 former microscopes. I have stated over and over again 

 that I have succeeded in getting a photograph with less 

 than the one-thonsandth part of the light that has 

 hitherto been considered necessary. Beyond a sixth on a 

 sixth, with one inch oculars, the image becomes so faint 

 as to be scarcely visible. 'Now, when I use higher ob- 

 jectives, or when I place a third microscope in tandem 

 with a double microscope, it is necessary to resort to a 

 techuic which enables me to photograph the invisible 

 image thus produced. This technic consist in eliminat- 

 ing from witliin the camera and microscope tubes all 

 traces of dust and aqueous vapor, and in enclosing the 

 entire system of microscopes and camera within an act- 

 inic-proof box so that the rays which produce the image 

 may act cumulatively. As a matter of fact, however, a 

 magnification far beyond that of a 16th objective can 

 easily be seen by the eye. The first statement that I 

 made with regard to this discovery was that with a sixth 

 incli objective in tlie first microscope and a two-third inch 

 objective in the second microscope, and with a powerful 

 source of light, such as an arc-lamp and parallelizing 

 lenses, I could get more magnification and greater defi- 

 nition than with the 16th inch lens. As far as I have 

 learned, whoever has tried this has admitted this state- 

 ment. It is not a matter of argument, but of proof, and 

 that proof I have on hand. I also said that by putting 

 higher objectives in place of the ones just named I could 

 get still greater magnification and detail, but that it 

 would be necessary to photograph the image because it 

 was too faint to be seen by the eye. I had one photograph 

 in which the magnification was so great as to show the 



