1898.] MICROSCOPICAL JOURNAL. 191 



you will see, if you will take the trouble to call at my 

 laboratory, the definition and detail can be strictly first 

 class, but that with my present arrangements in not 

 having all the parts upon the same bed-plate, it is al- 

 most impossible to adjust the camera without disarrang- 

 ing the focus. I have tried all of the usual test objects^ 

 such as the pygidium of a flea and the Amphipleura pel- 

 iucida, and the usual test lines, and I can find noth- 

 ing capable of being resolved with a 24th objective that 

 I cannot much better resolve with a 6th inch objective in 

 the first microscope and a half inch in the second. I 

 submit that if this be true, and I will be very glad if you 

 will call and see if it be true or not, we can place at the 

 disposal of biologists a much cheaper and much more 

 convenient and a much better microscope than the usual 

 high power lenses." 



I think I fully understand the influence of the cone 

 of light admitted by the objective, and so on. Long 

 before I commenced my recent microscopic experiments I 

 made myself familliar with the subject, and I am pre- 

 pared to show, in my laboratory, at any time, the re- 

 solving power of a half-inch objective on a sixth. With 

 two such lenses, one inch ocular, and an arc light, I can 

 show details in an object which cannot be shown with a 

 l-16th or a l-25th ! By using monochromatic light 

 I avoid chromatic aberation, and I have no false images." 



The authorities are all sceptical about this work because 

 the idea is not new. Many men have many times unsuc- 

 cessfully tried putting two microscopes together,but they 

 have never had the necessary light nor the photographing 

 apparatus attached. This combination constitutes the 

 novelty of Professor Grates' arrangement and the intense 

 light makes it efi"ective. 



Professor Gates published in the Popular Science News 

 last December, a lengthy account of his work illustrated 

 by: Photograph of the apparatus which magnifies 360,000 



